Aleksandr Rodin
Degree: PhD
Position: Assistant Professor
Affiliation: NUS Centre for Advanced 2D Materials /Yale-NUS
Research Type: Theory
Office: S16-06-13
Email: aleksandr.rodin@yale-nus.edu.sg
Contact: (65) 6601 7559
CA2DM Publications:
2023 |
Fang, Hanyan; Mahalingam, Harshitra; Li, Xinzhe; Han, Xu; Qiu, Zhizhan; Han, Yixuan; Noori, Keian; Dulal, Dikshant; Chen, Hongfei; Lyu, Pin; Yang, Tianhao; Li, Jing; Su, Chenliang; Chen, Wei; Cai, Yongqing; Neto, Castro A H; Novoselov, Kostya S; Rodin, Aleksandr; Lu, Jiong Atomically precise vacancy-assembled quantum antidots Journal Article NATURE NANOTECHNOLOGY, 18 (12), 2023, ISSN: 1748-3387. @article{ISI:001062548200002, title = {Atomically precise vacancy-assembled quantum antidots}, author = {Hanyan Fang and Harshitra Mahalingam and Xinzhe Li and Xu Han and Zhizhan Qiu and Yixuan Han and Keian Noori and Dikshant Dulal and Hongfei Chen and Pin Lyu and Tianhao Yang and Jing Li and Chenliang Su and Wei Chen and Yongqing Cai and Castro A H Neto and Kostya S Novoselov and Aleksandr Rodin and Jiong Lu}, doi = {10.1038/s41565-023-01495-z}, times_cited = {0}, issn = {1748-3387}, year = {2023}, date = {2023-08-31}, journal = {NATURE NANOTECHNOLOGY}, volume = {18}, number = {12}, publisher = {NATURE PORTFOLIO}, address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY}, abstract = {Patterning antidots, which are regions of potential hills that repel electrons, into well-defined antidot lattices creates fascinating artificial periodic structures, leading to anomalous transport properties and exotic quantum phenomena in two-dimensional systems. Although nanolithography has brought conventional antidots from the semiclassical regime to the quantum regime, achieving precise control over the size of each antidot and its spatial period at the atomic scale has remained challenging. However, attaining such control opens the door to a new paradigm, enabling the creation of quantum antidots with discrete quantum hole states, which, in turn, offer a fertile platform to explore novel quantum phenomena and hot electron dynamics in previously inaccessible regimes. Here we report an atomically precise bottom-up fabrication of a series of atomic-scale quantum antidots through a thermal-induced assembly of a chalcogenide single vacancy in PtTe2. Such quantum antidots consist of highly ordered single-vacancy lattices, spaced by a single Te atom, reaching the ultimate downscaling limit of antidot lattices. Increasing the number of single vacancies in quantum antidots strengthens the cumulative repulsive potential and consequently enhances the collective interference of multiple-pocket scattered quasiparticles inside quantum antidots, creating multilevel quantum hole states with a tunable gap from the telecom to far-infrared regime. Moreover, precisely engineered quantum hole states of quantum antidots are geometry protected and thus survive on oxygen substitutional doping. Therefore, single-vacancy-assembled quantum antidots exhibit unprecedented robustness and property tunability, positioning them as highly promising candidates for advancing quantum information and photocatalysis technologies.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Patterning antidots, which are regions of potential hills that repel electrons, into well-defined antidot lattices creates fascinating artificial periodic structures, leading to anomalous transport properties and exotic quantum phenomena in two-dimensional systems. Although nanolithography has brought conventional antidots from the semiclassical regime to the quantum regime, achieving precise control over the size of each antidot and its spatial period at the atomic scale has remained challenging. However, attaining such control opens the door to a new paradigm, enabling the creation of quantum antidots with discrete quantum hole states, which, in turn, offer a fertile platform to explore novel quantum phenomena and hot electron dynamics in previously inaccessible regimes. Here we report an atomically precise bottom-up fabrication of a series of atomic-scale quantum antidots through a thermal-induced assembly of a chalcogenide single vacancy in PtTe2. Such quantum antidots consist of highly ordered single-vacancy lattices, spaced by a single Te atom, reaching the ultimate downscaling limit of antidot lattices. Increasing the number of single vacancies in quantum antidots strengthens the cumulative repulsive potential and consequently enhances the collective interference of multiple-pocket scattered quasiparticles inside quantum antidots, creating multilevel quantum hole states with a tunable gap from the telecom to far-infrared regime. Moreover, precisely engineered quantum hole states of quantum antidots are geometry protected and thus survive on oxygen substitutional doping. Therefore, single-vacancy-assembled quantum antidots exhibit unprecedented robustness and property tunability, positioning them as highly promising candidates for advancing quantum information and photocatalysis technologies. |
Biswas, Hillol; Mahalingam, Harshitra; Rodin, Aleksandr Numerical package for QFT calculations of defect-induced phenomena in graphene Journal Article JOURNAL OF PHYSICS-CONDENSED MATTER , 35 (2), 2023, ISSN: 0953-8984. @article{ISI:000894023300001, title = {Numerical package for QFT calculations of defect-induced phenomena in graphene }, author = {Hillol Biswas and Harshitra Mahalingam and Aleksandr Rodin}, doi = {10.1088/1361-648X/aca002}, times_cited = {0}, issn = {0953-8984}, year = {2023}, date = {2023-01-18}, journal = {JOURNAL OF PHYSICS-CONDENSED MATTER }, volume = {35}, number = {2}, publisher = {IOP Publishing Ltd }, address = {TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND }, abstract = {We introduce a computationally efficient method based on the path integral formalism to describe defect-modified graphene. By taking into account the entire Brillouin zone, our approach respects the lattice symmetry and can be used to investigate both short-range and long-range effects. The proposed method's key advantage is that the computational complexity does not increase with the system size, scaling, instead, with the number of defects. Our aim is to make the quantum-field calculations in graphene accessible to the experimental community. We demonstrate our method's capabilities by exploring the well-known graphene-mediated Ruderman-Kittel-Kasuya-Yoshida interaction and by performing a detailed study of the atomic collapse in the presence of defects. }, keywords = {}, pubstate = {published}, tppubtype = {article} } We introduce a computationally efficient method based on the path integral formalism to describe defect-modified graphene. By taking into account the entire Brillouin zone, our approach respects the lattice symmetry and can be used to investigate both short-range and long-range effects. The proposed method's key advantage is that the computational complexity does not increase with the system size, scaling, instead, with the number of defects. Our aim is to make the quantum-field calculations in graphene accessible to the experimental community. We demonstrate our method's capabilities by exploring the well-known graphene-mediated Ruderman-Kittel-Kasuya-Yoshida interaction and by performing a detailed study of the atomic collapse in the presence of defects. |
Biswas, Hillol; Mahalingam, Harshitra; Rodin, Aleksandr Numerical package for QFT calculations of defect-induced phenomena in graphene Journal Article JOURNAL OF PHYSICS-CONDENSED MATTER, 35 (2), 2023, ISSN: 0953-8984. @article{ISI:000885188200001, title = {Numerical package for QFT calculations of defect-induced phenomena in graphene}, author = {Hillol Biswas and Harshitra Mahalingam and Aleksandr Rodin}, doi = {10.1088/1361-648X/aca002}, times_cited = {0}, issn = {0953-8984}, year = {2023}, date = {2023-01-18}, journal = {JOURNAL OF PHYSICS-CONDENSED MATTER}, volume = {35}, number = {2}, publisher = {IOP Publishing Ltd}, address = {TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND}, abstract = {We introduce a computationally efficient method based on the path integral formalism to describe defect-modified graphene. By taking into account the entire Brillouin zone, our approach respects the lattice symmetry and can be used to investigate both short-range and long-range effects. The proposed method's key advantage is that the computational complexity does not increase with the system size, scaling, instead, with the number of defects. Our aim is to make the quantum-field calculations in graphene accessible to the experimental community. We demonstrate our method's capabilities by exploring the well-known graphene-mediated Ruderman-Kittel-Kasuya-Yoshida interaction and by performing a detailed study of the atomic collapse in the presence of defects.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We introduce a computationally efficient method based on the path integral formalism to describe defect-modified graphene. By taking into account the entire Brillouin zone, our approach respects the lattice symmetry and can be used to investigate both short-range and long-range effects. The proposed method's key advantage is that the computational complexity does not increase with the system size, scaling, instead, with the number of defects. Our aim is to make the quantum-field calculations in graphene accessible to the experimental community. We demonstrate our method's capabilities by exploring the well-known graphene-mediated Ruderman-Kittel-Kasuya-Yoshida interaction and by performing a detailed study of the atomic collapse in the presence of defects. |
2022 |
Telychko, Mykola; Noori, Keian; Biswas, Hillol; Dulal, Dikshant; Chen, Zhaolong; Lyu, Pin; Li, Jing; Tsai, Hsin-Zon; Fang, Hanyan; Qiu, Zhizhan; Yap, Zhun Wai; Watanabe, Kenji; Taniguchi, Takashi; Wu, Jing; Loh, Kian Ping; Crommie, Michael F; Rodin, Aleksandr; Lu, Jiong Gate-Tunable Resonance State and Screening Effects for Proton-Like Atomic Charge in Graphene Journal Article NANO LETTERS, 2022, ISSN: 1530-6984. @article{ISI:000871063800001, title = {Gate-Tunable Resonance State and Screening Effects for Proton-Like Atomic Charge in Graphene}, author = {Mykola Telychko and Keian Noori and Hillol Biswas and Dikshant Dulal and Zhaolong Chen and Pin Lyu and Jing Li and Hsin-Zon Tsai and Hanyan Fang and Zhizhan Qiu and Zhun Wai Yap and Kenji Watanabe and Takashi Taniguchi and Jing Wu and Kian Ping Loh and Michael F Crommie and Aleksandr Rodin and Jiong Lu}, doi = {10.1021/acs.nanolett.2c02235}, times_cited = {0}, issn = {1530-6984}, year = {2022}, date = {2022-10-10}, journal = {NANO LETTERS}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {The ability to create a robust and well-defined artificial atomic charge in graphene and understand its carrier dependent electronic properties represents an important goal toward the development of graphene-based quantum devices. Herein, we devise a new pathway toward the atomically precise embodiment of point charges into a graphene lattice by posterior (N) ion implantation into a back-gated graphene device. The N dopant behaves as an in-plane proton-like charge manifested by formation of the characteristic resonance state in the conduction band. Scanning tunneling spectroscopy measurements at varied charge carrier densities reveal a giant energetic renormalization of the resonance state up to 220 meV with respect to the Dirac point, accompanied by the observation of gate-tunable long-range screening effects close to individual N dopants. Joint density functional theory and tight-binding calculations with modified perturbation potential corroborate experimental findings and highlight the short-range character of N-induced perturbation.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The ability to create a robust and well-defined artificial atomic charge in graphene and understand its carrier dependent electronic properties represents an important goal toward the development of graphene-based quantum devices. Herein, we devise a new pathway toward the atomically precise embodiment of point charges into a graphene lattice by posterior (N) ion implantation into a back-gated graphene device. The N dopant behaves as an in-plane proton-like charge manifested by formation of the characteristic resonance state in the conduction band. Scanning tunneling spectroscopy measurements at varied charge carrier densities reveal a giant energetic renormalization of the resonance state up to 220 meV with respect to the Dirac point, accompanied by the observation of gate-tunable long-range screening effects close to individual N dopants. Joint density functional theory and tight-binding calculations with modified perturbation potential corroborate experimental findings and highlight the short-range character of N-induced perturbation. |
Mayer, Rafael A; Feres, Flavio H; Maia, Francisco C B; Barcelos, Ingrid D; McLeod, Alexander S; Rodin, Aleksandr; Freitas, Raul O Guidelines for Engineering Directional Polariton Launchers Journal Article PHYSICAL REVIEW APPLIED, 18 (3), 2022, ISSN: 2331-7019. @article{ISI:000866515900003, title = {Guidelines for Engineering Directional Polariton Launchers}, author = {Rafael A Mayer and Flavio H Feres and Francisco C B Maia and Ingrid D Barcelos and Alexander S McLeod and Aleksandr Rodin and Raul O Freitas}, doi = {10.1103/PhysRevApplied.18.034089}, times_cited = {0}, issn = {2331-7019}, year = {2022}, date = {2022-09-30}, journal = {PHYSICAL REVIEW APPLIED}, volume = {18}, number = {3}, publisher = {AMER PHYSICAL SOC}, address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, abstract = {Nanophotonic devices based on two-dimensional crystals enable various technological applications, ranging from biosensing to quantum communication. In those devices, plasmonic antennas have been extensively explored in the photon-polariton conversion, as they allow field confinement within subdiffraction volumes. Despite the wide-reaching potential of polaritonics, essential rules for engineering polariton launchers are still to be developed, as the influence of the antenna geometry and source parameters on the polariton directivity is unknown. Here, we address this issue by combining concepts of radio-frequency antenna design with established polariton modeling. As an input for the model, we simulate hyperbolic phonon polariton waves in hexagonal boron nitride launched by metallic antennas. By adapting a Fresnel and Fraunhofer field regions formalism to polaritonics, we optimize the model accuracy and graphically represent several launching parameters as radiation patterns. Furthermore, we demonstrate how our framework can be applied to real antennas by employing it to experimental near-field images of polaritons reported in the literature. Our results show that the antenna geometry, its resonance order, and the angle of incidence of the light can strongly influence the polariton-wave pattern in the crystal. We foresee that our framework can add to further studies approaching optimized polariton launching and help the engineering of nanophotonic chips.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Nanophotonic devices based on two-dimensional crystals enable various technological applications, ranging from biosensing to quantum communication. In those devices, plasmonic antennas have been extensively explored in the photon-polariton conversion, as they allow field confinement within subdiffraction volumes. Despite the wide-reaching potential of polaritonics, essential rules for engineering polariton launchers are still to be developed, as the influence of the antenna geometry and source parameters on the polariton directivity is unknown. Here, we address this issue by combining concepts of radio-frequency antenna design with established polariton modeling. As an input for the model, we simulate hyperbolic phonon polariton waves in hexagonal boron nitride launched by metallic antennas. By adapting a Fresnel and Fraunhofer field regions formalism to polaritonics, we optimize the model accuracy and graphically represent several launching parameters as radiation patterns. Furthermore, we demonstrate how our framework can be applied to real antennas by employing it to experimental near-field images of polaritons reported in the literature. Our results show that the antenna geometry, its resonance order, and the angle of incidence of the light can strongly influence the polariton-wave pattern in the crystal. We foresee that our framework can add to further studies approaching optimized polariton launching and help the engineering of nanophotonic chips. |
Rodin, Aleksandr; Noori, Keian; Carvalho, Alexandra; Neto, Castro A H Microscopic theory of ionic motion in solids Journal Article PHYSICAL REVIEW B, 105 (22), 2022, ISSN: 2469-9950. @article{ISI:000823042500003, title = {Microscopic theory of ionic motion in solids}, author = {Aleksandr Rodin and Keian Noori and Alexandra Carvalho and Castro A H Neto}, doi = {10.1103/PhysRevB.105.224310}, times_cited = {0}, issn = {2469-9950}, year = {2022}, date = {2022-06-21}, journal = {PHYSICAL REVIEW B}, volume = {105}, number = {22}, publisher = {AMER PHYSICAL SOC}, address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, abstract = {Drag and diffusion of mobile ions in solids are of interest for both purely theoretical and applied scientific communities. This article proposes a theoretical description of ion drag in solids that can be used to estimate ionic conductivities in crystals, and forms a basis for the rational design of solid electrolyte materials. Starting with a general solid-state Hamiltonian, we employ the nonequilibrium path integral formalism to develop a microscopic theory of ionic transport in solids in the presence of thermal fluctuations. As required by the fluctuation-dissipation theorem, we obtain a relation between the variance of the random force and friction. Because of the crystalline nature of the system, however, the two quantities are tensorial. We use the drag tensor to write down the formula for ionic mobility, determined by the potential profile generated by the crystal???s ions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Drag and diffusion of mobile ions in solids are of interest for both purely theoretical and applied scientific communities. This article proposes a theoretical description of ion drag in solids that can be used to estimate ionic conductivities in crystals, and forms a basis for the rational design of solid electrolyte materials. Starting with a general solid-state Hamiltonian, we employ the nonequilibrium path integral formalism to develop a microscopic theory of ionic transport in solids in the presence of thermal fluctuations. As required by the fluctuation-dissipation theorem, we obtain a relation between the variance of the random force and friction. Because of the crystalline nature of the system, however, the two quantities are tensorial. We use the drag tensor to write down the formula for ionic mobility, determined by the potential profile generated by the crystal???s ions. |
Fang, Hanyan; Gallardo, Aurelio; Dulal, Dikshant; Qiu, Zhizhan; Su, Jie; Telychko, Mykola; Mahalingam, Harshitra; Lyu, Pin; Han, Yixuan; Zheng, Yi; Cai, Yongqing; Rodin, Aleksandr; Jelinek, Pavel; Lu, Jiong Electronic Self-Passivation of Single Vacancy in Black Phosphorus via Ionization Journal Article PHYSICAL REVIEW LETTERS, 128 (17), 2022, ISSN: 0031-9007. @article{ISI:000804572300005, title = {Electronic Self-Passivation of Single Vacancy in Black Phosphorus via Ionization}, author = {Hanyan Fang and Aurelio Gallardo and Dikshant Dulal and Zhizhan Qiu and Jie Su and Mykola Telychko and Harshitra Mahalingam and Pin Lyu and Yixuan Han and Yi Zheng and Yongqing Cai and Aleksandr Rodin and Pavel Jelinek and Jiong Lu}, doi = {10.1103/PhysRevLett.128.176801}, times_cited = {0}, issn = {0031-9007}, year = {2022}, date = {2022-04-26}, journal = {PHYSICAL REVIEW LETTERS}, volume = {128}, number = {17}, publisher = {AMER PHYSICAL SOC}, address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, abstract = {We report that monoelemental black phosphorus presents a new electronic self-passivation scheme of single vacancy (SV). By means of low-temperature scanning tunneling microscopy and noncontact atomic force microscopy, we demonstrate that the local reconstruction and ionization of SV into negatively charged SV??? leads to the passivation of dangling bonds and, thus, the quenching of in-gap states, which can be achieved by mild thermal annealing or STM tip manipulation. SV exhibits a strong and symmetric Friedel oscillation (FO) pattern, while SV??? shows an asymmetric FO pattern with local perturbation amplitude reduced by one order of magnitude and a faster decay rate. The enhanced passivation by forming SV??? can be attributed to its weak dipolelike perturbation, consistent with density-functional theory numerical calculations. Therefore, self-passivated SV??? is electrically benign and acts as a much weaker scattering center, which may hold the key to further enhance the charge mobility of black phosphorus and its analogs.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We report that monoelemental black phosphorus presents a new electronic self-passivation scheme of single vacancy (SV). By means of low-temperature scanning tunneling microscopy and noncontact atomic force microscopy, we demonstrate that the local reconstruction and ionization of SV into negatively charged SV??? leads to the passivation of dangling bonds and, thus, the quenching of in-gap states, which can be achieved by mild thermal annealing or STM tip manipulation. SV exhibits a strong and symmetric Friedel oscillation (FO) pattern, while SV??? shows an asymmetric FO pattern with local perturbation amplitude reduced by one order of magnitude and a faster decay rate. The enhanced passivation by forming SV??? can be attributed to its weak dipolelike perturbation, consistent with density-functional theory numerical calculations. Therefore, self-passivated SV??? is electrically benign and acts as a much weaker scattering center, which may hold the key to further enhance the charge mobility of black phosphorus and its analogs. |
2021 |
Peng, Xinnan; Mahalingam, Harshitra; Dong, Shaoqiang; Mutombo, Pingo; Su, Jie; Telychko, Mykola; Song, Shaotang; Lyu, Pin; Ng, Pei Wen; Wu, Jishan; Jelinek, Pavel; Chi, Chunyan; Rodin, Aleksandr; Lu, Jiong Visualizing designer quantum states in stable macrocycle quantum corrals Journal Article NATURE COMMUNICATIONS, 12 (1), 2021. @article{ISI:000705238300007, title = {Visualizing designer quantum states in stable macrocycle quantum corrals}, author = {Xinnan Peng and Harshitra Mahalingam and Shaoqiang Dong and Pingo Mutombo and Jie Su and Mykola Telychko and Shaotang Song and Pin Lyu and Pei Wen Ng and Jishan Wu and Pavel Jelinek and Chunyan Chi and Aleksandr Rodin and Jiong Lu}, doi = {10.1038/s41467-021-26198-8}, times_cited = {0}, year = {2021}, date = {2021-10-08}, journal = {NATURE COMMUNICATIONS}, volume = {12}, number = {1}, publisher = {NATURE PORTFOLIO}, address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY}, abstract = {Creating atomically-precise quantum architectures with high digital fidelity and desired quantum states is an important goal for quantum technology applications. Here the authors devise an on-surface synthetic protocol to construct atomically-precise covalently linked organic quantum corrals with the formation of a series of new quantum resonance states.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Creating atomically-precise quantum architectures with high digital fidelity and desired quantum states is an important goal for quantum technology applications. Here the authors devise an on-surface synthetic protocol to construct atomically-precise covalently linked organic quantum corrals with the formation of a series of new quantum resonance states. |
Lee, Gideon; Rodin, Aleksandr Phonon Casimir effect in polyatomic systems Journal Article PHYSICAL REVIEW B, 103 (19), 2021, ISSN: 2469-9950. @article{ISI:000655901600004, title = {Phonon Casimir effect in polyatomic systems}, author = {Gideon Lee and Aleksandr Rodin}, doi = {10.1103/PhysRevB.103.195434}, times_cited = {0}, issn = {2469-9950}, year = {2021}, date = {2021-05-24}, journal = {PHYSICAL REVIEW B}, volume = {103}, number = {19}, publisher = {AMER PHYSICAL SOC}, address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, abstract = {The phonon Casimir effect describes the phonon-mediated interaction between defects in condensed-matter systems. Using the path-integral formalism, we derive a general method for calculating the Helmholtz free energy due to vibrational modes in systems of arbitrary dimensionality and composition. Our results make it possible to extract the defect interaction energy at any temperature for various defect configurations. We demonstrate our approach in action by performing numerical calculations for mono- and diatomic chains, as well as a diatomic molecule, at zero and finite temperatures and validate our results using exact diagonalization.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The phonon Casimir effect describes the phonon-mediated interaction between defects in condensed-matter systems. Using the path-integral formalism, we derive a general method for calculating the Helmholtz free energy due to vibrational modes in systems of arbitrary dimensionality and composition. Our results make it possible to extract the defect interaction energy at any temperature for various defect configurations. We demonstrate our approach in action by performing numerical calculations for mono- and diatomic chains, as well as a diatomic molecule, at zero and finite temperatures and validate our results using exact diagonalization. |
2020 |
Noori, Keian; Quek, Su Ying; Rodin, Aleksandr Hydrogen adatoms on graphene: The role of hybridization and lattice distortion Journal Article PHYSICAL REVIEW B, 102 (19), 2020, ISSN: 2469-9950. @article{ISI:000588226400003, title = {Hydrogen adatoms on graphene: The role of hybridization and lattice distortion}, author = {Keian Noori and Su Ying Quek and Aleksandr Rodin}, doi = {10.1103/PhysRevB.102.195416}, times_cited = {0}, issn = {2469-9950}, year = {2020}, date = {2020-11-11}, journal = {PHYSICAL REVIEW B}, volume = {102}, number = {19}, publisher = {AMER PHYSICAL SOC}, address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, abstract = {By performing a detailed study of hydrogen adsorbates on graphene using density functional theory (DFT), we propose a general tight-binding (TB) formalism for a simultaneous treatment of multiple impurities of arbitrary species. To elucidate the details of the hydrogen-graphene bonding, we systematically examine the effects of hybridization and deformation on the band structure and the spectral function. An enhanced understanding of the binding mechanisms leads to a TB model whose predicted spectral function compares favorably with the DFT calculations on the scale of the supercell, as well as the individual adsorbates and carbon atoms. The computational load of our model scales with the number of impurities, not their separation, making it especially useful for experimentally relevant clustered impurity configurations that are too computationally expensive for DFT. The formalism described here allows for the treatment of Anderson impurities and impurities that bind to multiple carbon atoms.}, keywords = {}, pubstate = {published}, tppubtype = {article} } By performing a detailed study of hydrogen adsorbates on graphene using density functional theory (DFT), we propose a general tight-binding (TB) formalism for a simultaneous treatment of multiple impurities of arbitrary species. To elucidate the details of the hydrogen-graphene bonding, we systematically examine the effects of hybridization and deformation on the band structure and the spectral function. An enhanced understanding of the binding mechanisms leads to a TB model whose predicted spectral function compares favorably with the DFT calculations on the scale of the supercell, as well as the individual adsorbates and carbon atoms. The computational load of our model scales with the number of impurities, not their separation, making it especially useful for experimentally relevant clustered impurity configurations that are too computationally expensive for DFT. The formalism described here allows for the treatment of Anderson impurities and impurities that bind to multiple carbon atoms. |
Rodin, Aleksandr; Trushin, Maxim; Carvalho, Alexandra; Neto, Castro A H Collective excitations in 2D materials Journal Article NATURE REVIEWS PHYSICS, 2 (10), pp. 524-537, 2020. @article{ISI:000569258700001, title = {Collective excitations in 2D materials}, author = {Aleksandr Rodin and Maxim Trushin and Alexandra Carvalho and Castro A H Neto}, doi = {10.1038/s42254-020-0214-4}, times_cited = {0}, year = {2020}, date = {2020-09-07}, journal = {NATURE REVIEWS PHYSICS}, volume = {2}, number = {10}, pages = {524-537}, publisher = {SPRINGERNATURE}, address = {CAMPUS, 4 CRINAN ST, LONDON, N1 9XW, ENGLAND}, abstract = {Research on 2D materials has been one of the fastest-growing fields in condensed matter and materials science research in the past 10 years. The low dimensionality and strong correlations of 2D systems give rise to electronic and structural properties, in the form of collective excitations, that do not have counterparts in ordinary 3D materials used in modern technology. These 2D materials present extraordinary opportunities for new technologies, such as in flexible electronics. In this Review, we focus on plasmons, excitons, phonons and magnons in 2D materials. We discuss the theoretical formalism of these collective excitations and elucidate how they differ from their 3D counterparts.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Research on 2D materials has been one of the fastest-growing fields in condensed matter and materials science research in the past 10 years. The low dimensionality and strong correlations of 2D systems give rise to electronic and structural properties, in the form of collective excitations, that do not have counterparts in ordinary 3D materials used in modern technology. These 2D materials present extraordinary opportunities for new technologies, such as in flexible electronics. In this Review, we focus on plasmons, excitons, phonons and magnons in 2D materials. We discuss the theoretical formalism of these collective excitations and elucidate how they differ from their 3D counterparts. |
Noori, Keian; Biswas, Hillol; Quek, Su Ying; Rodin, Aleksandr Graphene-mediated interaction between hydrogen adsorbates Journal Article PHYSICAL REVIEW B, 101 (11), 2020, ISSN: 2469-9950. @article{ISI:000519990500007, title = {Graphene-mediated interaction between hydrogen adsorbates}, author = {Keian Noori and Hillol Biswas and Su Ying Quek and Aleksandr Rodin}, doi = {10.1103/PhysRevB.101.115421}, times_cited = {0}, issn = {2469-9950}, year = {2020}, date = {2020-03-18}, journal = {PHYSICAL REVIEW B}, volume = {101}, number = {11}, publisher = {AMER PHYSICAL SOC}, address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, abstract = {Interaction between adsorbed hydrogen atoms in graphene is studied using a combination of DFT and the path integral formalism. Our results reveal a complex nonmonotonic interaction profile. We show that the strength and sign of the interaction are dictated by the adsorbate arrangement, as well as the system doping. The path integral approach given here allows one to compute energies and densities in an efficient manner without relying on exact diagonalization.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Interaction between adsorbed hydrogen atoms in graphene is studied using a combination of DFT and the path integral formalism. Our results reveal a complex nonmonotonic interaction profile. We show that the strength and sign of the interaction are dictated by the adsorbate arrangement, as well as the system doping. The path integral approach given here allows one to compute energies and densities in an efficient manner without relying on exact diagonalization. |
2019 |
Rodin, Aleksandr Many-impurity phonon Casimir effect in atomic chains Journal Article PHYSICAL REVIEW B, 100 (19), 2019, ISSN: 2469-9950. @article{ISI:000494451700002, title = {Many-impurity phonon Casimir effect in atomic chains}, author = {Aleksandr Rodin}, doi = {10.1103/PhysRevB.100.195403}, times_cited = {0}, issn = {2469-9950}, year = {2019}, date = {2019-11-05}, journal = {PHYSICAL REVIEW B}, volume = {100}, number = {19}, publisher = {AMER PHYSICAL SOC}, address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, abstract = {The phonon Casimir effect is the long-range interaction between impurities in condensed matter systems, mediated by vacuum fluctuations of the phonon field. For pairs of impurities, this interaction has been shown to follow a quasi-power-law at zero-temperature and evolve into an exponentially decaying form as the temperature is increased. This work introduces an approach to deal with systems of more than two impurities, both at zero and finite temperatures.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The phonon Casimir effect is the long-range interaction between impurities in condensed matter systems, mediated by vacuum fluctuations of the phonon field. For pairs of impurities, this interaction has been shown to follow a quasi-power-law at zero-temperature and evolve into an exponentially decaying form as the temperature is increased. This work introduces an approach to deal with systems of more than two impurities, both at zero and finite temperatures. |
2018 |
Hanakata, Paul Z; Rodin, A S; Park, Harold S; Campbell, David K; Neto, Castro A H Strain-induced gauge and Rashba fields in ferroelectric Rashba lead chalcogenide PbX monolayers (X = S, Se, Te) Journal Article PHYSICAL REVIEW B, 97 (23), 2018, ISSN: 2469-9950. @article{ISI:000436625500005, title = {Strain-induced gauge and Rashba fields in ferroelectric Rashba lead chalcogenide Pb\textit{X} monolayers (\textit{X} = S, Se, Te)}, author = {Paul Z Hanakata and A S Rodin and Harold S Park and David K Campbell and Castro A H Neto}, doi = {10.1103/PhysRevB.97.235312}, times_cited = {0}, issn = {2469-9950}, year = {2018}, date = {2018-06-28}, journal = {PHYSICAL REVIEW B}, volume = {97}, number = {23}, publisher = {AMER PHYSICAL SOC}, address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, abstract = {One of the exciting features of two-dimensional (2D) materials is their electronic and optical tunability through strain engineering. Previously, we found a class of 2D ferroelectric Rashba semiconductors PbX (X = S, Se, Te) with tunable spin-orbital properties. In this work, based on our previous tight-binding (TB) results, we derive an effective low-energy Hamiltonian around the symmetry points that captures the effects of strain on the electronic properties of PbX. We find that strains induce gauge fields which shift the Rashba point and modify the Rashba parameter. This effect is equivalent to the application of in-plane magnetic fields. The out-of-plane strain, which is proportional to the electric polarization, is also shown to modify the Rashba parameter. Overall, our theory connects strain and spin splitting in ferroelectric Rashba materials, which will be important to understand the strain-induced variations in local Rashba parameters that will occur in practical applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } One of the exciting features of two-dimensional (2D) materials is their electronic and optical tunability through strain engineering. Previously, we found a class of 2D ferroelectric Rashba semiconductors PbX (X = S, Se, Te) with tunable spin-orbital properties. In this work, based on our previous tight-binding (TB) results, we derive an effective low-energy Hamiltonian around the symmetry points that captures the effects of strain on the electronic properties of PbX. We find that strains induce gauge fields which shift the Rashba point and modify the Rashba parameter. This effect is equivalent to the application of in-plane magnetic fields. The out-of-plane strain, which is proportional to the electric polarization, is also shown to modify the Rashba parameter. Overall, our theory connects strain and spin splitting in ferroelectric Rashba materials, which will be important to understand the strain-induced variations in local Rashba parameters that will occur in practical applications. |
Rodin, A S; Neto, Castro A H Localized magnetic states in two-dimensional semiconductors Journal Article PHYSICAL REVIEW B, 97 (23), 2018, ISSN: 2469-9950. @article{ISI:000435544900004, title = {Localized magnetic states in two-dimensional semiconductors}, author = {A S Rodin and Castro A H Neto}, doi = {10.1103/PhysRevB.97.235428}, times_cited = {0}, issn = {2469-9950}, year = {2018}, date = {2018-06-19}, journal = {PHYSICAL REVIEW B}, volume = {97}, number = {23}, publisher = {AMER PHYSICAL SOC}, address = {ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA}, abstract = {We study the formation of magnetic states in localized impurities embedded into two-dimensional semiconductors. By considering various energy configurations, we illustrate the interplay of the gap and the bands in the system magnetization. Finally, we consider finite-temperature effects to show how increasing T can lead to formation and destruction of magnetization.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We study the formation of magnetic states in localized impurities embedded into two-dimensional semiconductors. By considering various energy configurations, we illustrate the interplay of the gap and the bands in the system magnetization. Finally, we consider finite-temperature effects to show how increasing T can lead to formation and destruction of magnetization. |