Publications
2025 |
Hao, Qi; Liu, Yijun; Zou, Ren; Shi, Ge; Yang, Shilian; Zhong, Linxin; Yang, Wu; Chi, Xiao; Liu, Yunpeng; Admassie, Shimelis; Peng, Xinwen g-C3N4 nanosheets coupled with CoSe2 as co-catalyst for efficient photooxidation of xylose to xylonic acid Journal Article GREEN ENERGY & ENVIRONMENT, 10 (1), pp. 231-238, 2025, ISSN: 2096-2797. @article{ISI:001395719700001, title = {\textit{g}-C_{3}N_{4} nanosheets coupled with CoSe_{2} as co-catalyst for efficient photooxidation of xylose to xylonic acid}, author = {Qi Hao and Yijun Liu and Ren Zou and Ge Shi and Shilian Yang and Linxin Zhong and Wu Yang and Xiao Chi and Yunpeng Liu and Shimelis Admassie and Xinwen Peng}, doi = {10.1016/j.gee.2024.04.004}, times_cited = {0}, issn = {2096-2797}, year = {2025}, date = {2025-01-01}, journal = {GREEN ENERGY & ENVIRONMENT}, volume = {10}, number = {1}, pages = {231-238}, publisher = {KEAI PUBLISHING LTD}, address = {16 DONGHUANGCHENGGEN NORTH ST, Building 5, Room 411, BEIJING, DONGCHENG DISTRICT 100009, PEOPLES R CHINA}, abstract = {Photocatalysis has emerged as an effective approach to sustainably convert biomass into value-added products. CoSe2 is a promising non-precious, efficient cocatalyst for photooxidation, which can facilitate the separation of photogenerated electron-holes, increase the reaction rates, and enhance photocatalytic efficiency. In this work, we synthesized a stable and efficient photocatalysis system of CoSe2/g-C3N4 through attaching CoSe2 on g-C3N4 sheets, with a yield of 50.12% for the selective photooxidation of xylose to xylonic acid. Under light illumination, the photogenerated electrons were prone to migrating from g-C3N4 to CoSe2 due to the higher work function of CoSe2, resulting in the accelerated separation of photogenerated electron-holes and the promoted photooxidation. Herein, this study reveals the unique function of CoSe2, which can significantly promote oxygen adsorption, work as an electron sink and accelerate the generation of center dot O-2, thereby improving the selectivity toward xylonic acid over other by-products. This work provides useful insights into the design of selective photocatalysts by engineering g-C3N4 for biomass high-value utilization. (c) 2025 Institute of Process Engineering, Chinese Academy of Sciences. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Photocatalysis has emerged as an effective approach to sustainably convert biomass into value-added products. CoSe2 is a promising non-precious, efficient cocatalyst for photooxidation, which can facilitate the separation of photogenerated electron-holes, increase the reaction rates, and enhance photocatalytic efficiency. In this work, we synthesized a stable and efficient photocatalysis system of CoSe2/g-C3N4 through attaching CoSe2 on g-C3N4 sheets, with a yield of 50.12% for the selective photooxidation of xylose to xylonic acid. Under light illumination, the photogenerated electrons were prone to migrating from g-C3N4 to CoSe2 due to the higher work function of CoSe2, resulting in the accelerated separation of photogenerated electron-holes and the promoted photooxidation. Herein, this study reveals the unique function of CoSe2, which can significantly promote oxygen adsorption, work as an electron sink and accelerate the generation of center dot O-2, thereby improving the selectivity toward xylonic acid over other by-products. This work provides useful insights into the design of selective photocatalysts by engineering g-C3N4 for biomass high-value utilization. (c) 2025 Institute of Process Engineering, Chinese Academy of Sciences. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co., Ltd. |
Morin, Julien Luc Paul; Dubey, Nileshkumar; Luong-Van, Emma Kim; Yu, Baiqing; Sabino, Clarice Ferreira; Silikas, Nick; Agarwalla, Shruti Vidhawan; Neto, Castro A H; Rosa, Vinicius Graphene nanocoating on titanium maintains structural and antibiofilm properties post-sterilization Journal Article DENTAL MATERIALS, 41 (1), pp. 7-15, 2025, ISSN: 0109-5641. @article{ISI:001391110500001, title = {Graphene nanocoating on titanium maintains structural and antibiofilm properties post-sterilization}, author = {Julien Luc Paul Morin and Nileshkumar Dubey and Emma Kim Luong-Van and Baiqing Yu and Clarice Ferreira Sabino and Nick Silikas and Shruti Vidhawan Agarwalla and Castro A H Neto and Vinicius Rosa}, doi = {10.1016/j.dental.2024.10.009}, times_cited = {0}, issn = {0109-5641}, year = {2025}, date = {2025-01-01}, journal = {DENTAL MATERIALS}, volume = {41}, number = {1}, pages = {7-15}, publisher = {ELSEVIER SCI LTD}, address = {125 London Wall, London, ENGLAND}, abstract = {Objective: To evaluate the impact of sterilization methods on the structural integrity and antimicrobial properties of graphene nanocoating on titanium (GN). Methods: GN was transferred to titanium using wet (WT) or dry transfer (DT) techniques and sterilized using an autoclave (AC), glutaraldehyde (GA), or ethylene oxide (EtO). The GN structure was characterized using Raman spectroscopy before and after sterilization. Additional specimens were characterized by Raman after AC and water jetting. Biofilm formation was assessed before and after AC using colony-forming units (CFU), biofilm biomass, and SEM (uncoated titanium was the control). Three independent samples were used for structural characterization and biofilm quantification. Statistical analyses were conducted using one-way analysis of variance (ANOVA) and Tukey's test (alpha = 0.05). Results: WT and DT demonstrated high structural stability after sterilization and water jetting, with negligible coating quality or coverage loss. GN exhibited lower biofilm formation even after AC sterilization, as shown by the reduction in CFU counts, biofilm biomass, and SEM images compared to the control. Significance: GN demonstrated high resistance to the stresses imposed by all sterilization methods tested, maintaining its structural integrity, resistance to water-jet cleaning, and antibiofilm potential. The findings suggest that standard industrial practices can effectively sterilize highly resilient GN on titanium implants and possibly other biomaterials.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Objective: To evaluate the impact of sterilization methods on the structural integrity and antimicrobial properties of graphene nanocoating on titanium (GN). Methods: GN was transferred to titanium using wet (WT) or dry transfer (DT) techniques and sterilized using an autoclave (AC), glutaraldehyde (GA), or ethylene oxide (EtO). The GN structure was characterized using Raman spectroscopy before and after sterilization. Additional specimens were characterized by Raman after AC and water jetting. Biofilm formation was assessed before and after AC using colony-forming units (CFU), biofilm biomass, and SEM (uncoated titanium was the control). Three independent samples were used for structural characterization and biofilm quantification. Statistical analyses were conducted using one-way analysis of variance (ANOVA) and Tukey's test (alpha = 0.05). Results: WT and DT demonstrated high structural stability after sterilization and water jetting, with negligible coating quality or coverage loss. GN exhibited lower biofilm formation even after AC sterilization, as shown by the reduction in CFU counts, biofilm biomass, and SEM images compared to the control. Significance: GN demonstrated high resistance to the stresses imposed by all sterilization methods tested, maintaining its structural integrity, resistance to water-jet cleaning, and antibiofilm potential. The findings suggest that standard industrial practices can effectively sterilize highly resilient GN on titanium implants and possibly other biomaterials. |
2024 |
Ezzi, Mohammed Al M; Pallewela, Gayani N; Beule, Christophe De; Mele, E J; Adam, Shaffique Analytical Model for Atomic Relaxation in Twisted Moire PHYSICAL REVIEW LETTERS, 133 (26), 2024, ISSN: 0031-9007. @article{ISI:001386385200014, title = {Analytical Model for Atomic Relaxation in Twisted Moire author = {Mohammed Al M Ezzi and Gayani N Pallewela and Christophe De Beule and E J Mele and Shaffique Adam}, doi = {10.1103/PhysRevLett.133.266201}, times_cited = {0}, issn = {0031-9007}, year = {2024}, date = {2024-12-23}, journal = {PHYSICAL REVIEW LETTERS}, volume = {133}, number = {26}, publisher = {AMER PHYSICAL SOC}, address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, abstract = {By virtue of being atomically thin, the electronic properties of heterostructures built from twodimensional materials are strongly influenced by atomic relaxation. The atomic layers behave as flexible membranes rather than rigid crystals. Here we develop an analytical theory of lattice relaxation in twisted moire keywords = {}, pubstate = {published}, tppubtype = {article} } By virtue of being atomically thin, the electronic properties of heterostructures built from twodimensional materials are strongly influenced by atomic relaxation. The atomic layers behave as flexible membranes rather than rigid crystals. Here we develop an analytical theory of lattice relaxation in twisted moire |
Zhang, Lishu; Yuan, Zhengping; Yang, Jie; Zhou, Jun; Jiang, Yanyan; Li, Hui; Cai, Yongqing; Tsymbal, Evgeny Y; Feng, Yuan Ping; Zhu, Zhifeng; Shen, Lei Van der Waals spin-orbit torque antiferromagnetic memory Journal Article PHYSICAL REVIEW B, 110 (22), 2024, ISSN: 2469-9950. @article{ISI:001389463600001, title = {Van der Waals spin-orbit torque antiferromagnetic memory}, author = {Lishu Zhang and Zhengping Yuan and Jie Yang and Jun Zhou and Yanyan Jiang and Hui Li and Yongqing Cai and Evgeny Y Tsymbal and Yuan Ping Feng and Zhifeng Zhu and Lei Shen}, doi = {10.1103/PhysRevB.110.L220409}, times_cited = {1}, issn = {2469-9950}, year = {2024}, date = {2024-12-20}, journal = {PHYSICAL REVIEW B}, volume = {110}, number = {22}, publisher = {AMER PHYSICAL SOC}, address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, abstract = {The technique of conventional ferromagnet/heavy-metal spin-orbit torque (SOT) offers significant potential for enhancing the efficiency of magnetic memories. However, it faces fundamental physical limitations, including shunting effects from the metallic layer, broken symmetry for enabling antidamping switching, spin scattering caused by interfacial defects, and sensitivity to stray magnetic fields. To address these issues, we here propose a van der Waals (vdW) field-free SOT antiferromagnetic memory using a vdW bilayer LaBr2 (an antiferromagnet with perpendicular magnetic anisotropy) and a monolayer Td phase WTe2 (a Weyl semimetal with broken inversion symmetry). By systematically employing density functional theory in conjunction with nonequilibrium Green's function methods and macrospin simulations, we demonstrate that the proposed vdW SOT devices exhibit remarkably low critical current density approximately 10 MA/cm2 and rapid field-free magnetization switching in 250 ps. This facilitates excellent write performance with extremely low energy consumption. Furthermore, the device shows a significantly low read error rate, as evidenced by a high tunnel magnetoresistance ratio of up to 4250%. The superior write and read performance originates from the unique strong on-site (insulating phase) and off-site (magnetic phase) Coulomb interactions in electride LaBr2, a large nonzero z-component polarization in WTe2, and the proximity effect between them.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The technique of conventional ferromagnet/heavy-metal spin-orbit torque (SOT) offers significant potential for enhancing the efficiency of magnetic memories. However, it faces fundamental physical limitations, including shunting effects from the metallic layer, broken symmetry for enabling antidamping switching, spin scattering caused by interfacial defects, and sensitivity to stray magnetic fields. To address these issues, we here propose a van der Waals (vdW) field-free SOT antiferromagnetic memory using a vdW bilayer LaBr2 (an antiferromagnet with perpendicular magnetic anisotropy) and a monolayer Td phase WTe2 (a Weyl semimetal with broken inversion symmetry). By systematically employing density functional theory in conjunction with nonequilibrium Green's function methods and macrospin simulations, we demonstrate that the proposed vdW SOT devices exhibit remarkably low critical current density approximately 10 MA/cm2 and rapid field-free magnetization switching in 250 ps. This facilitates excellent write performance with extremely low energy consumption. Furthermore, the device shows a significantly low read error rate, as evidenced by a high tunnel magnetoresistance ratio of up to 4250%. The superior write and read performance originates from the unique strong on-site (insulating phase) and off-site (magnetic phase) Coulomb interactions in electride LaBr2, a large nonzero z-component polarization in WTe2, and the proximity effect between them. |
Lu, Bin; Niu, Yue; Chen, Qian; Wong, Ping Kwan Johnny; Guo, Qingjie; Jiang, Wei; Rath, Ashutosh; Pennycook, Stephen J; Wang, Lei; Xia, Ke; Zhai, Ya; Wee, Andrew Thye Shen; Zhang, Wen Is Semiconducting Transition-Metal Dichalcogenide Suitable for Spin Pumping? Journal Article NANO LETTERS, 25 (1), pp. 35-40, 2024, ISSN: 1530-6984. @article{ISI:001379965300001, title = {Is Semiconducting Transition-Metal Dichalcogenide Suitable for Spin Pumping?}, author = {Bin Lu and Yue Niu and Qian Chen and Ping Kwan Johnny Wong and Qingjie Guo and Wei Jiang and Ashutosh Rath and Stephen J Pennycook and Lei Wang and Ke Xia and Ya Zhai and Andrew Thye Shen Wee and Wen Zhang}, doi = {10.1021/acs.nanolett.4c03469}, times_cited = {0}, issn = {1530-6984}, year = {2024}, date = {2024-12-17}, journal = {NANO LETTERS}, volume = {25}, number = {1}, pages = {35-40}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {Spin pumping has been reported on interfaces formed with ferromagnetic metals and layered transition-metal dichalcogenides (TMDs), as signified by enhanced Gilbert damping parameters extracted from magnetodynamics measurements. However, whether the observed damping enhancement purely arises from the pumping effect has remained debatable, given that possible extrinsic disturbances on the interfaces cannot be excluded in most of the experiments. Here, we explore an atomically clean interface formed with CoFeB and atomically thin MoSe2, achieved by an all in situ growth strategy based on molecular beam epitaxy. Taking advantage of ferromagnetic resonance analysis, we find that the Gilbert damping of the CoFeB/MoSe2 interface closely resembles that of CoFeB/SiO2, suggesting the absence of spin pumping. With similar findings demonstrated on a few more representative interfaces, this work clarifies the unsuitability of semiconducting TMDs for spin pumping and suggests that the observed damping enhancement in the previous reports may be predominantly attributed to extrinsic contributions during the experimental process.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Spin pumping has been reported on interfaces formed with ferromagnetic metals and layered transition-metal dichalcogenides (TMDs), as signified by enhanced Gilbert damping parameters extracted from magnetodynamics measurements. However, whether the observed damping enhancement purely arises from the pumping effect has remained debatable, given that possible extrinsic disturbances on the interfaces cannot be excluded in most of the experiments. Here, we explore an atomically clean interface formed with CoFeB and atomically thin MoSe2, achieved by an all in situ growth strategy based on molecular beam epitaxy. Taking advantage of ferromagnetic resonance analysis, we find that the Gilbert damping of the CoFeB/MoSe2 interface closely resembles that of CoFeB/SiO2, suggesting the absence of spin pumping. With similar findings demonstrated on a few more representative interfaces, this work clarifies the unsuitability of semiconducting TMDs for spin pumping and suggests that the observed damping enhancement in the previous reports may be predominantly attributed to extrinsic contributions during the experimental process. |
Guo, Qiangbing; Wu, Yun-Kun; Zhang, Di; Zhang, Qiuhong; Guo, Guang-Can; Alu, Andrea; Ren, Xi-Feng; Qiu, Cheng-Wei Polarization entanglement enabled by orthogonally stacked van der Waals NbOCl2 crystals Journal Article NATURE COMMUNICATIONS, 15 (1), 2024. @article{ISI:001376827800011, title = {Polarization entanglement enabled by orthogonally stacked van der Waals NbOCl_{2} crystals}, author = {Qiangbing Guo and Yun-Kun Wu and Di Zhang and Qiuhong Zhang and Guang-Can Guo and Andrea Alu and Xi-Feng Ren and Cheng-Wei Qiu}, doi = {10.1038/s41467-024-54876-w}, times_cited = {0}, year = {2024}, date = {2024-12-02}, journal = {NATURE COMMUNICATIONS}, volume = {15}, number = {1}, publisher = {NATURE PORTFOLIO}, address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY}, abstract = {Polarization entanglement holds significant importance for photonic quantum technologies. Recently emerging subwavelength nonlinear quantum light sources, e.g., GaP and LiNbO3 thin films, benefiting from the relaxed phase-matching constraints and volume confinement, have shown intriguing properties, such as high-dimensional hyperentanglement and robust entanglement anti-degradation. Van der Waals (vdW) NbOCl2 crystal, with strong optical nonlinearities, has emerged as a potential candidate for ultrathin quantum light sources. However, polarization entanglement is inaccessible in the NbOCl2 crystal due to its unfavorable nonlinear susceptibility tensor. Here, by leveraging the twist-stacking degree of freedom inherently in vdW systems, we showcase the preparation of polarization entanglement and quantum Bell states.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Polarization entanglement holds significant importance for photonic quantum technologies. Recently emerging subwavelength nonlinear quantum light sources, e.g., GaP and LiNbO3 thin films, benefiting from the relaxed phase-matching constraints and volume confinement, have shown intriguing properties, such as high-dimensional hyperentanglement and robust entanglement anti-degradation. Van der Waals (vdW) NbOCl2 crystal, with strong optical nonlinearities, has emerged as a potential candidate for ultrathin quantum light sources. However, polarization entanglement is inaccessible in the NbOCl2 crystal due to its unfavorable nonlinear susceptibility tensor. Here, by leveraging the twist-stacking degree of freedom inherently in vdW systems, we showcase the preparation of polarization entanglement and quantum Bell states. |
Loh, Leyi; Ho, Yi Wei; Xuan, Fengyuan; del Aguila, Andres Granados; Chen, Yuan; Wong, See Yoong; Zhang, Jingda; Wang, Zhe; Watanabe, Kenji; Taniguchi, Takashi; Pigram, Paul J; Bosman, Michel; Quek, Su Ying; Koperski, Maciej; Eda, Goki Nb impurity-bound excitons as quantum emitters in monolayer WS2 Journal Article NATURE COMMUNICATIONS, 15 (1), 2024. @article{ISI:001360396900001, title = {Nb impurity-bound excitons as quantum emitters in monolayer WS_{2}}, author = {Leyi Loh and Yi Wei Ho and Fengyuan Xuan and Andres Granados del Aguila and Yuan Chen and See Yoong Wong and Jingda Zhang and Zhe Wang and Kenji Watanabe and Takashi Taniguchi and Paul J Pigram and Michel Bosman and Su Ying Quek and Maciej Koperski and Goki Eda}, doi = {10.1038/s41467-024-54360-5}, times_cited = {0}, year = {2024}, date = {2024-11-20}, journal = {NATURE COMMUNICATIONS}, volume = {15}, number = {1}, publisher = {NATURE PORTFOLIO}, address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY}, abstract = {Point defects in crystalline solids behave as optically addressable individual quantum systems when present in sufficiently low concentrations. In two-dimensional (2D) semiconductors, such quantum defects hold potential as versatile single photon sources. Here, we report the synthesis and optical properties of Nb-doped monolayer WS2 in the dilute limit where the average spacing between individual dopants exceeds the optical diffraction limit, allowing the emission spectrum to be studied at the single-dopant level. We show that these individual dopants exhibit common features of quantum emitters, including narrow emission lines (with linewidths <1 meV), strong spatial confinement, and photon antibunching. These emitters consistently occur within a narrow spectral range across multiple samples, distinct from common quantum emitters in van der Waals (vdW) materials that show large ensemble broadening. Analysis of the Zeeman splitting reveals that they can be attributed to bound exciton complexes comprising dark excitons and negatively charged Nb.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Point defects in crystalline solids behave as optically addressable individual quantum systems when present in sufficiently low concentrations. In two-dimensional (2D) semiconductors, such quantum defects hold potential as versatile single photon sources. Here, we report the synthesis and optical properties of Nb-doped monolayer WS2 in the dilute limit where the average spacing between individual dopants exceeds the optical diffraction limit, allowing the emission spectrum to be studied at the single-dopant level. We show that these individual dopants exhibit common features of quantum emitters, including narrow emission lines (with linewidths <1 meV), strong spatial confinement, and photon antibunching. These emitters consistently occur within a narrow spectral range across multiple samples, distinct from common quantum emitters in van der Waals (vdW) materials that show large ensemble broadening. Analysis of the Zeeman splitting reveals that they can be attributed to bound exciton complexes comprising dark excitons and negatively charged Nb. |
Erofeev, Ivan; Hartanto, Antony Winata; Khan, Muhaimin Mareum; Deng, Kerong; Kumar, Krishna; Aabdin, Zainul; Tjiu, Weng Weei; Zhang, Mingsheng; Pacco, Antoine; Philipsen, Harold; Chowdhuri, Angshuman Ray; Huynh, Han Vinh; Holsteyns, Frank; Mirsaidov, Utkur Digital Etching of Molybdenum Interconnects Using Plasma Oxidation Journal Article ADVANCED MATERIALS INTERFACES, 12 (1), 2024, ISSN: 2196-7350. @article{ISI:001357050400001, title = {Digital Etching of Molybdenum Interconnects Using Plasma Oxidation}, author = {Ivan Erofeev and Antony Winata Hartanto and Muhaimin Mareum Khan and Kerong Deng and Krishna Kumar and Zainul Aabdin and Weng Weei Tjiu and Mingsheng Zhang and Antoine Pacco and Harold Philipsen and Angshuman Ray Chowdhuri and Han Vinh Huynh and Frank Holsteyns and Utkur Mirsaidov}, doi = {10.1002/admi.202400558}, times_cited = {0}, issn = {2196-7350}, year = {2024}, date = {2024-11-12}, journal = {ADVANCED MATERIALS INTERFACES}, volume = {12}, number = {1}, publisher = {WILEY}, address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA}, abstract = {Molybdenum (Mo) has a high potential of becoming the material of choice for sub-10 nm scale metal structures in future integrated circuits (ICs). Manufacturing at this scale requires exceptional precision and consistency, so many metal processing techniques must be reconsidered. In particular, present direct wet chemical etching methods produce anisotropic etching profiles with significant surface roughness, which can be detrimental to device performance. Here, it is shown that polycrystalline Mo nanowires can be etched uniformly using a cyclic two-step "digital" method: the metal surface is first oxidized with isotropic oxygen plasma to form a layer of MoO3, which is then selectively removed using either wet chemical or dry isotropic plasma etching. These two steps are repeated in cycles until the intended metal recess is achieved. High uniformity of plasma oxidation defines the etching uniformity, and small metal recess per cycle (typically 1-2 nm) provides precise control over the etching depth. This method can replace wet etching where high etching precision is needed, enabling the reliable manufacturing of nanoscale metal interconnects.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Molybdenum (Mo) has a high potential of becoming the material of choice for sub-10 nm scale metal structures in future integrated circuits (ICs). Manufacturing at this scale requires exceptional precision and consistency, so many metal processing techniques must be reconsidered. In particular, present direct wet chemical etching methods produce anisotropic etching profiles with significant surface roughness, which can be detrimental to device performance. Here, it is shown that polycrystalline Mo nanowires can be etched uniformly using a cyclic two-step "digital" method: the metal surface is first oxidized with isotropic oxygen plasma to form a layer of MoO3, which is then selectively removed using either wet chemical or dry isotropic plasma etching. These two steps are repeated in cycles until the intended metal recess is achieved. High uniformity of plasma oxidation defines the etching uniformity, and small metal recess per cycle (typically 1-2 nm) provides precise control over the etching depth. This method can replace wet etching where high etching precision is needed, enabling the reliable manufacturing of nanoscale metal interconnects. |
Ratwani, Chirag R; Donato, Katarzyna Z; Grebenchuk, Sergey; Mija, Alice; Novoselov, Kostya S; Abdelkader, Amr M Enhanced Self-Healing in Dual Network Entangled Hydrogels by Macromolecular Architecture and Alignent of Surface Functionalized hBN Nanosheets Journal Article ADVANCED MATERIALS INTERFACES, 2024, ISSN: 2196-7350. @article{ISI:001357180100001, title = {Enhanced Self-Healing in Dual Network Entangled Hydrogels by Macromolecular Architecture and Alignent of Surface Functionalized hBN Nanosheets}, author = {Chirag R Ratwani and Katarzyna Z Donato and Sergey Grebenchuk and Alice Mija and Kostya S Novoselov and Amr M Abdelkader}, doi = {10.1002/admi.202400691}, times_cited = {0}, issn = {2196-7350}, year = {2024}, date = {2024-10-31}, journal = {ADVANCED MATERIALS INTERFACES}, publisher = {WILEY}, address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA}, abstract = {Hydrogels have shown great promise as versatile biomaterials for various applications, ranging from tissue engineering to flexible electronics. Among their notable attributes, self-healing capabilities stand out as a significant advantage, facilitating autonomous repair of mechanical damage and restoration of structural integrity. In this work, a dual network macromolecular biphasic composite is designed using an anisotropic structure which facilitates unidirectional chain diffusion and imparts superior self-healing and mechanical properties. The resulting nanocomposite demonstrates significantly higher self-healing efficiency (92%) compared to traditional polyvinyl alcohol (PVA) hydrogels, while also improving the tensile strength and elastic modulus, which typically compete with each other in soft materials. This improvement is attributed to enhanced barrier properties within the matrix due to the alignment of surface-functionalized 2D hBN nanosheets along the biopolymer scaffold. The insights gained from this research can be leveraged to develop advanced self-healing materials by using 2D nanofillers as "safety barriers" to define the movement of polymeric chains.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Hydrogels have shown great promise as versatile biomaterials for various applications, ranging from tissue engineering to flexible electronics. Among their notable attributes, self-healing capabilities stand out as a significant advantage, facilitating autonomous repair of mechanical damage and restoration of structural integrity. In this work, a dual network macromolecular biphasic composite is designed using an anisotropic structure which facilitates unidirectional chain diffusion and imparts superior self-healing and mechanical properties. The resulting nanocomposite demonstrates significantly higher self-healing efficiency (92%) compared to traditional polyvinyl alcohol (PVA) hydrogels, while also improving the tensile strength and elastic modulus, which typically compete with each other in soft materials. This improvement is attributed to enhanced barrier properties within the matrix due to the alignment of surface-functionalized 2D hBN nanosheets along the biopolymer scaffold. The insights gained from this research can be leveraged to develop advanced self-healing materials by using 2D nanofillers as "safety barriers" to define the movement of polymeric chains. |
Wang, Dingguan; Haposan, Tobias; Fan, Jinwei; Arramel, ; Wee, Andrew T S Recent Progress of Imaging Chemical Bonds by Scanning Probe Microscopy: A Review Journal Article ACS NANO, 18 (45), pp. 30919-30942, 2024, ISSN: 1936-0851. @article{ISI:001345125600001, title = {Recent Progress of Imaging Chemical Bonds by Scanning Probe Microscopy: A Review}, author = {Dingguan Wang and Tobias Haposan and Jinwei Fan and Arramel and Andrew T S Wee}, doi = {10.1021/acsnano.4c10522}, times_cited = {0}, issn = {1936-0851}, year = {2024}, date = {2024-10-30}, journal = {ACS NANO}, volume = {18}, number = {45}, pages = {30919-30942}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {In the past decades, the invention of scanning probe microscopy (SPM) as the versatile surface-based characterization of organic molecules has triggered significant interest throughout multidisciplinary fields. In particular, the bond-resolved imaging acquired by SPM techniques has extended its fundamental function of not only unraveling the chemical structure but also allowing us to resolve the structure-property relationship. Here, we present a systematical review on the history of chemical bonds imaged by means of noncontact atomic force microscopy (nc-AFM) and bond-resolved scanning tunneling microscopy (BR-STM) techniques. We first summarize the advancement of real-space imaging of covalent bonds and the investigation of intermolecular noncovalent bonds. Beyond the bond imaging, we also highlight the applications of the bond-resolved SPM techniques such as on-surface synthesis, the determination of the reaction pathway, the identification of molecular configurations and unknown products, and the generation of artificial molecules created via tip manipulation. Lastly, we discuss the current status of SPM techniques and highlight several key technical challenges that must be solved in the coming years. In comparison to the existing reviews, this work invokes researchers from surface science, chemistry, condensed matter physics, and theoretical physics to uncover the bond-resolved SPM technique as an emerging tool in exploiting the molecule/surface system and their future applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In the past decades, the invention of scanning probe microscopy (SPM) as the versatile surface-based characterization of organic molecules has triggered significant interest throughout multidisciplinary fields. In particular, the bond-resolved imaging acquired by SPM techniques has extended its fundamental function of not only unraveling the chemical structure but also allowing us to resolve the structure-property relationship. Here, we present a systematical review on the history of chemical bonds imaged by means of noncontact atomic force microscopy (nc-AFM) and bond-resolved scanning tunneling microscopy (BR-STM) techniques. We first summarize the advancement of real-space imaging of covalent bonds and the investigation of intermolecular noncovalent bonds. Beyond the bond imaging, we also highlight the applications of the bond-resolved SPM techniques such as on-surface synthesis, the determination of the reaction pathway, the identification of molecular configurations and unknown products, and the generation of artificial molecules created via tip manipulation. Lastly, we discuss the current status of SPM techniques and highlight several key technical challenges that must be solved in the coming years. In comparison to the existing reviews, this work invokes researchers from surface science, chemistry, condensed matter physics, and theoretical physics to uncover the bond-resolved SPM technique as an emerging tool in exploiting the molecule/surface system and their future applications. |
Deng, Kerong; Erofeev, Ivan; Chowdhuri, Angshuman Ray; Philipsen, Harold; Aabdin, Zainul; Hartanto, Antony Winata; Tjiu, Weng Weei; Zhang, Mingsheng; Fernando, Devshan; Saidov, Khakimjon; Kumar, Krishna; Pacco, Antoine; Holsteyns, Frank; Huynh, Han Vinh; Mirsaidov, Utkur Nanoscale Wet Etching of Molybdenum Interconnects with Organic Solutions Journal Article SMALL, 20 (51), 2024, ISSN: 1613-6810. @article{ISI:001337998600001, title = {Nanoscale Wet Etching of Molybdenum Interconnects with Organic Solutions}, author = {Kerong Deng and Ivan Erofeev and Angshuman Ray Chowdhuri and Harold Philipsen and Zainul Aabdin and Antony Winata Hartanto and Weng Weei Tjiu and Mingsheng Zhang and Devshan Fernando and Khakimjon Saidov and Krishna Kumar and Antoine Pacco and Frank Holsteyns and Han Vinh Huynh and Utkur Mirsaidov}, doi = {10.1002/smll.202406713}, times_cited = {0}, issn = {1613-6810}, year = {2024}, date = {2024-10-22}, journal = {SMALL}, volume = {20}, number = {51}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {Molybdenum (Mo) has emerged as a promising material for advanced semiconductor devices, especially in the design and fabrication of interconnects requiring sub-10 nm metal nanostructures. However, current wet etching methods for Mo using aqueous solutions struggle to achieve smooth etching profiles at such scales. To address this problem, we explore wet chemical etching of patterned Mo nanowires (NWs) using an organic solution: ceric ammonium nitrate (CAN) dissolved in acetonitrile (ACN). In this study, we demonstrate two distinct etching pathways by controlling the reaction temperature: i) digital cyclic scheme at room temperature, with a self-limiting Mo recess per cycle of approximate to 1.6 nm, and ii) direct etching at elevated temperature (60 degrees C), with a time-controlled Mo recess of approximate to 2 nm min-1. These methods not only offer a highly controllable nanoscale Mo etching but also ensure smooth and uniform etching profiles independent of the crystal grain orientation of the metal.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Molybdenum (Mo) has emerged as a promising material for advanced semiconductor devices, especially in the design and fabrication of interconnects requiring sub-10 nm metal nanostructures. However, current wet etching methods for Mo using aqueous solutions struggle to achieve smooth etching profiles at such scales. To address this problem, we explore wet chemical etching of patterned Mo nanowires (NWs) using an organic solution: ceric ammonium nitrate (CAN) dissolved in acetonitrile (ACN). In this study, we demonstrate two distinct etching pathways by controlling the reaction temperature: i) digital cyclic scheme at room temperature, with a self-limiting Mo recess per cycle of approximate to 1.6 nm, and ii) direct etching at elevated temperature (60 degrees C), with a time-controlled Mo recess of approximate to 2 nm min-1. These methods not only offer a highly controllable nanoscale Mo etching but also ensure smooth and uniform etching profiles independent of the crystal grain orientation of the metal. |
Tang, Ho-Kin; Yudhistira, Indra; Chattopadhyay, Udvas; Ulybyshev, Maksim; Sengupta, P; Assaad, F F; Adam, S Spectral functions of lattice fermions on the honeycomb lattice with Hubbard and long-range Coulomb interactions Journal Article PHYSICAL REVIEW B, 110 (15), 2024, ISSN: 2469-9950. @article{ISI:001334829900007, title = {Spectral functions of lattice fermions on the honeycomb lattice with Hubbard and long-range Coulomb interactions}, author = {Ho-Kin Tang and Indra Yudhistira and Udvas Chattopadhyay and Maksim Ulybyshev and P Sengupta and F F Assaad and S Adam}, doi = {10.1103/PhysRevB.110.155120}, times_cited = {1}, issn = {2469-9950}, year = {2024}, date = {2024-10-09}, journal = {PHYSICAL REVIEW B}, volume = {110}, number = {15}, publisher = {AMER PHYSICAL SOC}, address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, abstract = {The absence of screening of the nonlocal Coulomb interaction in Dirac systems at charge neutrality leads to the breakdown of the Fermi liquid and divergence of the Fermi velocity. On the other hand, Mott-Hubbard physics and the concomitant formation of local moments is dominated by the local effective Hubbard interaction. Using quantum Monte Carlo methods combined with stochastic analytical continuation, we compute the single particle spectral function of fermions on the honeycomb lattice for a realistic interaction that includes both the Hubbard interaction and long-ranged Coulomb repulsion. To a first approximation, we find that the generic high-energy features, such as the formation of the upper Hubbard band near the phase transition, are primarily determined by the local effective Hubbard interaction. In the weakly interacting regime, the long-range Coulomb interaction enhances the bandwidth of quasiparticles and suppresses their lifetime. Conversely, near the phase transition, the long-range Coulomb interaction suppresses the background antiferromagnetic fluctuation, which potentially promotes the propagation of spin polarons, leading to a slight enhancement of the quasiparticle spectral weight and lifetime.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The absence of screening of the nonlocal Coulomb interaction in Dirac systems at charge neutrality leads to the breakdown of the Fermi liquid and divergence of the Fermi velocity. On the other hand, Mott-Hubbard physics and the concomitant formation of local moments is dominated by the local effective Hubbard interaction. Using quantum Monte Carlo methods combined with stochastic analytical continuation, we compute the single particle spectral function of fermions on the honeycomb lattice for a realistic interaction that includes both the Hubbard interaction and long-ranged Coulomb repulsion. To a first approximation, we find that the generic high-energy features, such as the formation of the upper Hubbard band near the phase transition, are primarily determined by the local effective Hubbard interaction. In the weakly interacting regime, the long-range Coulomb interaction enhances the bandwidth of quasiparticles and suppresses their lifetime. Conversely, near the phase transition, the long-range Coulomb interaction suppresses the background antiferromagnetic fluctuation, which potentially promotes the propagation of spin polarons, leading to a slight enhancement of the quasiparticle spectral weight and lifetime. |
Carrio, Juan A G; Echeverrigaray, Sergio G; Talluri, V S S L P; Sudhakaran, Deepa P; Gan, Hui T; Gardeno, Daniel; Friess, Karel; Neto, Antonio Castro H Performance of GO laminated membranes in H2/CO2 separation as a function of the membrane thickness Journal Article INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, 90 , pp. 646-654, 2024, ISSN: 0360-3199. @article{ISI:001332104500001, title = {Performance of GO laminated membranes in H2/CO2 separation as a function of the membrane thickness}, author = {Juan A G Carrio and Sergio G Echeverrigaray and V S S L P Talluri and Deepa P Sudhakaran and Hui T Gan and Daniel Gardeno and Karel Friess and Antonio Castro H Neto}, doi = {10.1016/j.ijhydene.2024.09.435}, times_cited = {0}, issn = {0360-3199}, year = {2024}, date = {2024-10-08}, journal = {INTERNATIONAL JOURNAL OF HYDROGEN ENERGY}, volume = {90}, pages = {646-654}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {Hydrogen gas (H2) is a promising energy carrier capable of replacing fossil fuels and achieving net zero emissions. However, purifying H2 for applications like fuel cells and industrial processes is challenging due to impurities affecting performance. Two-dimensional (2D) materials, particularly graphene-based membranes, are promising for H2 purification due to their unique properties. The hydrogen (H2) permeation capability of graphene-based membranes is particularly significant. This study examines the use of commercial and costeffective graphene oxide (GO) to fabricate multilayer graphene membranes, focusing on the impact of membrane thickness on H2 and CO2 separation. By using a scalable vacuum filtration method to coat porous ceramic substrates, membranes with controlled thicknesses were produced and characterised using AFM, FESEM, XRD, and gas permeation measurements. The study identified an optimal membrane thickness range (4 nm-250 nm) and the GO quantity (0.44 mu g/cm2 to 1.76 mu g/cm2) needed for effective H2/CO2 separation. This research aims to guide the development of cost-effective, mass-produced 2D-based membranes for industrial H2 purification.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Hydrogen gas (H2) is a promising energy carrier capable of replacing fossil fuels and achieving net zero emissions. However, purifying H2 for applications like fuel cells and industrial processes is challenging due to impurities affecting performance. Two-dimensional (2D) materials, particularly graphene-based membranes, are promising for H2 purification due to their unique properties. The hydrogen (H2) permeation capability of graphene-based membranes is particularly significant. This study examines the use of commercial and costeffective graphene oxide (GO) to fabricate multilayer graphene membranes, focusing on the impact of membrane thickness on H2 and CO2 separation. By using a scalable vacuum filtration method to coat porous ceramic substrates, membranes with controlled thicknesses were produced and characterised using AFM, FESEM, XRD, and gas permeation measurements. The study identified an optimal membrane thickness range (4 nm-250 nm) and the GO quantity (0.44 mu g/cm2 to 1.76 mu g/cm2) needed for effective H2/CO2 separation. This research aims to guide the development of cost-effective, mass-produced 2D-based membranes for industrial H2 purification. |
Chen, Mingyao; Liu, Huimin; He, Xu; Li, Minjuan; Tang, Chi Sin; Sun, Mengxia; Koirala, Krishna Prasad; Bowden, Mark E; Li, Yangyang; Liu, Xiongfang; Zhou, Difan; Sun, Shuo; Breese, Mark B H; Cai, Chuanbing; Wang, Le; Du, Yingge; Wee, Andrew T S; Yin, Xinmao Uncovering an Interfacial Band Resulting from Orbital Hybridization in Nickelate Heterostructures Journal Article ACS NANO, 18 (40), pp. 27707-27717, 2024, ISSN: 1936-0851. @article{ISI:001324763700001, title = {Uncovering an Interfacial Band Resulting from Orbital Hybridization in Nickelate Heterostructures}, author = {Mingyao Chen and Huimin Liu and Xu He and Minjuan Li and Chi Sin Tang and Mengxia Sun and Krishna Prasad Koirala and Mark E Bowden and Yangyang Li and Xiongfang Liu and Difan Zhou and Shuo Sun and Mark B H Breese and Chuanbing Cai and Le Wang and Yingge Du and Andrew T S Wee and Xinmao Yin}, doi = {10.1021/acsnano.4c09921}, times_cited = {0}, issn = {1936-0851}, year = {2024}, date = {2024-09-26}, journal = {ACS NANO}, volume = {18}, number = {40}, pages = {27707-27717}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {The interaction of atomic orbitals at the interface of perovskite oxide heterostructures has been investigated for its profound impact on the band structures and electronic properties, giving rise to unique electronic states and a variety of tunable functionalities. In this study, we conducted an extensive investigation of the optical and electronic properties of epitaxial NdNiO3 synthesized on a series of single-crystal substrates. Unlike nanofilms synthesized on other substrates, NdNiO3 on SrTiO3 (NNO/STO) gives rise to a unique band structure featuring an additional unoccupied band situated above the Fermi level. Our comprehensive investigation, which incorporated a wide array of experimental techniques and density functional theory calculations, revealed that the emergence of the interfacial band structure is primarily driven by orbital hybridization between the Ti 3d orbitals of the STO substrate and the O 2p orbitals of the NNO thin film. Furthermore, exciton peaks have been detected in the optical spectra of the NNO/STO film, attributable to the pronounced electron-electron (e-e) and electron-hole (e-h) interactions propagating from the STO substrate into the NNO film. These findings underscore the substantial influence of interfacial orbital hybridization on the electronic structure of oxide thin films, thereby offering key insights into tuning their interfacial properties.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The interaction of atomic orbitals at the interface of perovskite oxide heterostructures has been investigated for its profound impact on the band structures and electronic properties, giving rise to unique electronic states and a variety of tunable functionalities. In this study, we conducted an extensive investigation of the optical and electronic properties of epitaxial NdNiO3 synthesized on a series of single-crystal substrates. Unlike nanofilms synthesized on other substrates, NdNiO3 on SrTiO3 (NNO/STO) gives rise to a unique band structure featuring an additional unoccupied band situated above the Fermi level. Our comprehensive investigation, which incorporated a wide array of experimental techniques and density functional theory calculations, revealed that the emergence of the interfacial band structure is primarily driven by orbital hybridization between the Ti 3d orbitals of the STO substrate and the O 2p orbitals of the NNO thin film. Furthermore, exciton peaks have been detected in the optical spectra of the NNO/STO film, attributable to the pronounced electron-electron (e-e) and electron-hole (e-h) interactions propagating from the STO substrate into the NNO film. These findings underscore the substantial influence of interfacial orbital hybridization on the electronic structure of oxide thin films, thereby offering key insights into tuning their interfacial properties. |
Huang, Jianwei; Setty, Chandan; Deng, Liangzi; You, Jing-Yang; Liu, Hongxiong; Shao, Sen; Oh, Ji Seop; Guo, Yucheng; Zhang, Yichen; Yue, Ziqin; Yin, Jia-Xin; Hashimoto, Makoto; Lu, Donghui; Gorovikov, Sergey; Dai, Pengcheng; Denlinger, Jonathan D; Allen, J W; Hasan, Zahid M; Feng, Yuan-Ping; Birgeneau, Robert J; Shi, Youguo; Chu, Ching-Wu; Chang, Guoqing; Si, Qimiao; Yi, Ming Observation of flat bands and Dirac cones in a pyrochlore lattice superconductor Journal Article NPJ QUANTUM MATERIALS, 9 (1), 2024. @article{ISI:001316044100001, title = {Observation of flat bands and Dirac cones in a pyrochlore lattice superconductor}, author = {Jianwei Huang and Chandan Setty and Liangzi Deng and Jing-Yang You and Hongxiong Liu and Sen Shao and Ji Seop Oh and Yucheng Guo and Yichen Zhang and Ziqin Yue and Jia-Xin Yin and Makoto Hashimoto and Donghui Lu and Sergey Gorovikov and Pengcheng Dai and Jonathan D Denlinger and J W Allen and Zahid M Hasan and Yuan-Ping Feng and Robert J Birgeneau and Youguo Shi and Ching-Wu Chu and Guoqing Chang and Qimiao Si and Ming Yi}, doi = {10.1038/s41535-024-00683-x}, times_cited = {3}, year = {2024}, date = {2024-09-19}, journal = {NPJ QUANTUM MATERIALS}, volume = {9}, number = {1}, publisher = {NATURE PORTFOLIO}, address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY}, abstract = {Emergent phases often appear when the electronic kinetic energy is comparable to the Coulomb interactions. One approach to seek material systems as hosts of such emergent phases is to realize localization of electronic wavefunctions due to the geometric frustration inherent in the crystal structure, resulting in flat electronic bands. Recently, such efforts have found a wide range of exotic phases in the two-dimensional kagome lattice, including magnetic order, time-reversal symmetry breaking charge order, nematicity, and superconductivity. However, the interlayer coupling of the kagome layers disrupts the destructive interference needed to completely quench the kinetic energy. Here we demonstrate that an interwoven kagome network-a pyrochlore lattice-can host a three dimensional (3D) localization of electron wavefunctions. Meanwhile, the nonsymmorphic symmetry of the pyrochlore lattice guarantees all band crossings at the Brillouin zone X point to be 3D gapless Dirac points, which was predicted theoretically but never yet observed experimentally. Through a combination of angle-resolved photoemission spectroscopy, fundamental lattice model and density functional theory calculations, we investigate the novel electronic structure of a Laves phase superconductor with a pyrochlore sublattice, CeRu2. We observe evidence of flat bands originating from the Ce 4f orbitals as well as flat bands from the 3D destructive interference of the Ru 4d orbitals. We further observe the nonsymmorphic symmetry-protected 3D gapless Dirac cone at the X point. Our work establishes the pyrochlore structure as a promising lattice platform to realize and tune novel emergent phases intertwining topology and many-body interactions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Emergent phases often appear when the electronic kinetic energy is comparable to the Coulomb interactions. One approach to seek material systems as hosts of such emergent phases is to realize localization of electronic wavefunctions due to the geometric frustration inherent in the crystal structure, resulting in flat electronic bands. Recently, such efforts have found a wide range of exotic phases in the two-dimensional kagome lattice, including magnetic order, time-reversal symmetry breaking charge order, nematicity, and superconductivity. However, the interlayer coupling of the kagome layers disrupts the destructive interference needed to completely quench the kinetic energy. Here we demonstrate that an interwoven kagome network-a pyrochlore lattice-can host a three dimensional (3D) localization of electron wavefunctions. Meanwhile, the nonsymmorphic symmetry of the pyrochlore lattice guarantees all band crossings at the Brillouin zone X point to be 3D gapless Dirac points, which was predicted theoretically but never yet observed experimentally. Through a combination of angle-resolved photoemission spectroscopy, fundamental lattice model and density functional theory calculations, we investigate the novel electronic structure of a Laves phase superconductor with a pyrochlore sublattice, CeRu2. We observe evidence of flat bands originating from the Ce 4f orbitals as well as flat bands from the 3D destructive interference of the Ru 4d orbitals. We further observe the nonsymmorphic symmetry-protected 3D gapless Dirac cone at the X point. Our work establishes the pyrochlore structure as a promising lattice platform to realize and tune novel emergent phases intertwining topology and many-body interactions. |