Hillol Biswas
Group: Prof Quek Su Ying
CA2DM Publications:
2023 |
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 = {8}, 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. |
2020 |
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 = {4}, 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. |