Article
Chemistry, Multidisciplinary
Jizhe Song, Zhongyuan Zhang, Naixing Feng, Jingang Wang
Summary: The external electric field can modulate the spectrum and electronic structure behavior of twisted bilayer graphene (TBG) by driving the relative positions of the conduction band and valence band, causing significant changes in spectrum behavior.
Article
Multidisciplinary Sciences
Youngjoon Choi, Hyunjin Kim, Yang Peng, Alex Thomson, Cyprian Lewandowski, Robert Polski, Yiran Zhang, Harpreet Singh Arora, Kenji Watanabe, Takashi Taniguchi, Jason Alicea, Stevan Nadj-Perge
Summary: Magic-angle twisted bilayer graphene (MATBG) exhibits a variety of correlated phenomena, and new techniques introduced can determine the topological phases that emerge in MATBG in a finite magnetic field. These topological phases form only in a specific range of twist angles and are influenced by strong electronic interactions.
Article
Physics, Condensed Matter
Nguyen Van Men, Nguyen Quoc Khanh, Dong Thi Kim Phuong
Summary: This study calculates the plasmon frequency and damping rate of plasma oscillations in a spin-polarized bilayer graphene system. It shows that the degree of spin polarization has a negligible effect on the long wavelength plasmon frequency but affects the damping rate and frequency changes with increasing spin polarization. Moreover, an increase in carrier density significantly decreases both the plasmon frequency and damping rate, while the critical wave vector decreases with spin polarization and can be used to experimentally determine the degree of spin polarization.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2021)
Review
Materials Science, Multidisciplinary
Yindi Wang, Hongxia Liu, Shulong Wang, Ming Cai
Summary: This paper presents a waveguide-integrated graphene-based modulator with excellent performance, including 100% modulation depth, low power dissipation, small device size, and wide bandwidth. The modulator shows robustness and tolerance to fabrication errors, making it highly promising in the field of optoelectronic integrated circuits.
Article
Materials Science, Multidisciplinary
Ting Wang, Jianfeng Liu, Keji Miao, Yangyang Yin, Junjie Ma, Shibin Yin, Weiguo Pan
Summary: This study compared the oxygen reduction reaction activity of materials with different structures such as single-doped N, single-doped Pt, and double-layer graphene co-doped with N and Pt. By establishing models and calculating the adsorption energy, it was found that platinum-decorated and nitrogen-doped BLG had better oxygen reduction activity, and surface adsorption was also better than interlayer adsorption.
JOURNAL OF MATERIALS SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Andrea Tomadin, Matteo Carrega, Marco Polini
Summary: This study investigates the theory of plasma-wave photodetection in bilayer graphene, demonstrating how quantum capacitance effects can modify the intensity of the photodetection signal. External electrical bias induced by top and bottom gates can be used to control the strength of quantum capacitance corrections and thus the photoresponse.
Article
Multidisciplinary Sciences
Xiaoxue Liu, Zhi Wang, K. Watanabe, T. Taniguchi, Oskar Vafek, J. I. A. Li
Summary: This study introduces a new device geometry to continuously tune the strength of electron-electron Coulomb interaction within twisted bilayer graphene, revealing opposite effects of charge screening on insulating and superconducting states.
Article
Chemistry, Multidisciplinary
Jiayu Zhang, Junyi Li, Shuxian Chen, Kunhua Wen, Wenjie Liu
Summary: This study proposes a terahertz metamaterial structure composed of a silicon-graphene-silicon sandwich, aiming to achieve quadruple plasmon-induced transparency (PIT). The results obtained from the coupled mode theory (CMT) calculations align with the simulations ones using the finite difference time domain (FDTD) method. The modulation depths (MDs) and insertion losses (ILs) obtained at specific frequencies demonstrate multiple switching effects and potential applications in modulators and optical switches in the terahertz range.
Article
Chemistry, Multidisciplinary
Yong-Qiang Liu, Zhongru Ren, Hongcheng Yin, Jinhai Sun, Liangsheng Li
Summary: This paper presents the dispersion theory and modal characteristics of graphene metasurfaces featuring surface plasmon polaritons (SPPs). The obtained dispersion expressions show the splitting of SPPs into two new modes on the double-layer graphene metasurface. The study investigates the dispersion relation and propagating properties as a function of key physical parameters, indicating great potential for constructing various novel plasmonic devices in the Terahertz band.
Article
Chemistry, Physical
Xiangyan Luo, Yixin Wang, Zean Tian, Jiajun Ma, Hong Yu, Quan Xie
Summary: This paper explores the stability and physical properties of double-walled carbon nanotubes and the bilayer graphene obtained from their unfolding. It examines the influence of tube diameter and chiral index on the stability and metallization trend of carbon nanotubes.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Physics, Condensed Matter
Yawar Mohammadi
Summary: The study of plasmon modes in doped AA-stacked bilayer graphene reveals the potential of using it as a tunable plasmonic device. The long-wavelength acoustic plasmon's existence is hindered as the chemical potential approaches the interlayer hopping energy. Optimal long-lived optical plasmon in undoped AA-stacked BLG can be achieved by satisfying specific conditions.
SUPERLATTICES AND MICROSTRUCTURES
(2021)
Article
Physics, Applied
Fengqi Zhou, Yuqing Wang, Xiao Zhang, Jiawei Wang, Zhimin Liu, Xin Luo, Zhenbin Zhang, Enduo Gao
Summary: A bilayer metamaterial consisting of double graphene strips and square-ring graphene is proposed to achieve plasmon induced transparency (PIT). Dynamic adjustable PIT is investigated by modulating the Fermi levels of graphene and adjusting the coupling distance between the two graphene structures, showing that PIT gradually disappears with increasing coupling distance. The clear relationships between dips of PIT and modes of CMT are described, which are influenced by the relative location of resonant points of bright and dark modes.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Physics, Multidisciplinary
Yuan Da Liao, Jian Kang, Clara N. Breio, Xiao Yan Xu, Han-Qing Wu, Brian M. Andersen, Rafael M. Fernandes, Zi Yang Meng
Summary: In this study, unbiased quantum Monte Carlo simulations were used to solve an effective interacting lattice model for twisted bilayer graphene (TBG) at charge neutrality. Various correlated insulating phases were discovered, including a quantum valley Hall state with topological edge states, an intervalley-coherent insulator, and a valence bond solid. These charge-neutrality correlated insulating phases provide important reference states for understanding insulating states at integer fillings and the proximate superconducting states of TBG.
Article
Spectroscopy
Xiangtao Chen, Chen Lu, Li Wang, Jingang Wang
Summary: This paper qualitatively and quantitatively analyzes the one-photon absorption (OPA) spectrum and two-photon absorption (TPA) spectrum, as well as the electronic excitation, charge transfer, partial density of states (PDOS), and magnetic induction current density of zigzag edge twisted bilayer graphene quantum dots (Z-TwBLG-QDs) with different twisted angles. The effects of Moire superlatrate (MS) and PDOS on inter-layer local excitation and intra-layer charge transfer are discussed. The results show that the twisted angle plays a decisive role in the absorption spectrum and the twisted angle can regulate the TPA cross section and the boundary effect of Z-TwBLG-QDs in a specific wavelength range. The physical mechanism of how the twisted angle regulates electron transition behavior is revealed through magnetic induction current density analysis.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2022)
Article
Nanoscience & Nanotechnology
Feng-Lin Shyu
Summary: Band structures of bilayer armchair graphene nanoribbons (BLAGNRs) are calculated under an electric field in the tight-binding model. The electric field induces oscillatory band-gaps, leading to transitions between semiconductor and metal. The dielectric function is evaluated to obtain plasmon spectra, which are affected by temperature and exhibit different momentum-dependences.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2023)
Article
Physics, Condensed Matter
Phuong Dong Thi Kim, Men Van Nguyen
Summary: In this study, we calculated collective excitations and damping rate in a double layer structure comprising one monolayer gapped graphene sheet and a GaAs quantum well using random-phase approximation at zero temperature. We found that both in-phase optical and out-of-phase acoustic plasmon modes exist in the system, with different responses to quantum well width and exchange-correlation effects. Taking into account local-field correction led to a decrease in only the AC plasmon frequency, mainly in the large wave-vectors region.
EUROPEAN PHYSICAL JOURNAL B
(2021)
Article
Physics, Condensed Matter
Nguyen Van Men, Nguyen Quoc Khanh, Dong Thi Kim Phuong
Summary: This study calculates the plasmon frequency and damping rate of plasma oscillations in a spin-polarized bilayer graphene system. It shows that the degree of spin polarization has a negligible effect on the long wavelength plasmon frequency but affects the damping rate and frequency changes with increasing spin polarization. Moreover, an increase in carrier density significantly decreases both the plasmon frequency and damping rate, while the critical wave vector decreases with spin polarization and can be used to experimentally determine the degree of spin polarization.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2021)
Article
Physics, Applied
Van-Men Nguyen, Kim-Phuong Thi Dong
Summary: The study investigates plasmon excitations in a double-layer structure, revealing the existence of two plasmon modes in the system. The optical mode continues in the interband single-particle excitation area, while the acoustic mode only crosses the intraband single-particle excitation boundary and disappears. Plasmon frequency is affected by separation and carrier density, with temperature having a weaker impact on plasmon properties compared to other factors.
JOURNAL OF LOW TEMPERATURE PHYSICS
(2021)
Article
Physics, Condensed Matter
Nguyen Van Men, Dong Thi Kim Phuong
Summary: This study investigates collective excitations in a double-layer graphene structure through numerical calculations, finding that temperature, doping density, and carrier density have significant effects on plasmon frequencies.
SOLID STATE COMMUNICATIONS
(2021)
Article
Physics, Applied
Kim-Phuong Dong-Thi, Van-Men Nguyen
Summary: The study reveals that the plasmon properties of four parallel monolayer graphene (4-MLG) sheets in an inhomogeneous background dielectric differ significantly from those in a homogeneous system, resulting in smaller plasmon frequencies and different directions of acoustic plasmon branch movement.
JOURNAL OF LOW TEMPERATURE PHYSICS
(2022)
Article
Physics, Condensed Matter
Nguyen Van Men
Summary: In this study, the plasmon properties in N-layer silicene systems were investigated, considering the spin-orbit coupling effect. The results show that the frequencies of plasmonic collective excitations increase with the number of layers and are less influenced by the bandgap. Furthermore, the imbalanced carrier density between silicene layers significantly affects the plasmon frequencies.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2022)
Article
Physics, Condensed Matter
Nguyen Van Men, Nguyen Quoc Khanh, Dang Khanh Linh
Summary: The study explores zero-temperature plasmon modes in a double-layer bilayer graphene structure under a perpendicular electrostatic bias. Results show the presence of two undamped collective modes in the long wavelength limit, with the finite potential bias significantly decreasing the plasmon energy and causing Landau damping at higher wave-vectors. The dependence of plasmon dispersions on system parameters remains similar with and without electrostatic bias.
PHYSICA B-CONDENSED MATTER
(2022)
Article
Nanoscience & Nanotechnology
Van-Men Nguyen
Summary: This study investigates the effects of temperature and the inhomogeneity of background dielectric on collective excitations in a multilayer graphene structure. The results indicate that temperature affects the acoustic plasmon frequency and the optical plasmon frequency in different ways. Additionally, temperature causes energy loss in the plasmon modes, even outside the single-particle excitation region. The inhomogeneity of background dielectric reduces plasmon energy and damping rate, as well as the influence of temperature and interlayer separation on collective excitations.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2022)
Article
Physics, Applied
Dong Thi Kim Phuong, Nguyen Van Men
Summary: We studied the frictional drag phenomenon in a double-layer system consisting of two parallel gapped graphene layers by calculating the Coulomb drag resistivity. The Coulomb drag resistivity in double-layer gapped graphene systems shows interesting different features compared to other double-layer systems. The temperature steadily increases the Coulomb drag resistivity in the system, while the interlayer distance quickly decreases it. A finite bandgap has remarkable contributions to the frictional drag phenomenon, and it is necessary to consider this factor in calculations for better agreement with experimental works.
INTERNATIONAL JOURNAL OF MODERN PHYSICS B
(2023)
Article
Physics, Multidisciplinary
V-M Nguyen
Summary: In this study, the Coulomb bare interactions in a 5-layer graphene structure were analytically calculated in an inhomogeneous background dielectric. The results showed that the inhomogeneity of the dielectric environment significantly affected the intra- and interlayer Coulomb bare interactions, leading to noticeable differences in values at critical momentum. Additionally, in the long-wavelength limit, interactions between charged particles in the structure were found to depend only on the dielectric constant of the outermost layers.
INDIAN JOURNAL OF PHYSICS
(2022)
