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Analysis and Modeling of White Graphene Physical Properties for Sensor Applications
摘要： White graphene as a two-dimensional material has honeycomb lattice which is comprised of boron and nitrogen atoms. Its mechanical properties are similar to graphene, but its electrical properties are different because it has a large bandgap about 5.5 eV. Moreover, relaxation time plays a key role in its properties that affects on the electron transfer speed in this material. The white graphene is an insulator, but its dielectric polarization does not depend on the electric ?eld and also any external stress cannot change linear response of relaxation. In this research, some physical properties of white graphene and its relaxation time are investigated and modeled. Finally, acceptable results are reported which bring new hopes for the replacement of silicon oxide with white graphene as a one-monolayer insulator in future sensors applications.
关键词： Honeycomb lattice,Graphene,Bandgap,Two-dimensional materials,White graphene
更新于2025-09-23 15:23:52
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Photonic band structure in a 2D honeycomb lattice of triangular holes
摘要： In this study, we calculate the photonic band structure for a honeycomb two-dimensional photonic crystal lattice composed triangular holes embedded in GaAs. We assume that the GaAs dielectric function depends on the applied hydrostatic pressure and temperature. The plane wave expansion method is used to calculate the PBS for transverse electric (TE) and transverse magnetic (TM) polarizations. At constant temperature, we find that if the hydrostatic pressure increases, the PBS for both polarizations shifts to higher energies without modifying the gap width. On removing a triangular hole from the structure, both gap position and width remain unchanged for TM polarizations with the presence of a defective band whose energy is tuned to pressure increases.
关键词： Triangular holes,Plane wave expansion method,Honeycomb lattice,Photonic crystal
更新于2025-09-23 15:22:29
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Field dependence of THz spectra of effective models for <i>α</i> -RuCl <sub/>3</sub>
摘要： We calculate polarized terahertz (THz) spectra of two effective models for a honeycomb-lattice magnet α-RuCl3 by using a numerical exact-diagonalization method. One of the two models is the ab initio model proposed in H.-S. Kim and H.-Y. Kee [Phys. Rev. B 93, 155143 (2016)] and the other is the large-|K| model that we have proposed by an empirical way in order to explain experimental results for α-RuCl3. We discuss the magnetic-?eld dependence of the lowest-excitation mode in the polarized THz spectra for the two models. We ?nd that the energy gap of the lowest-excitation mode in both models does not close and increases almost linearly above the critical ?eld, where the zigzag order is suppressed. From the obtained results, we point out that the low-energy excitation is mainly governed not by the Kitaev interaction but by the Heisenberg interaction and the off-diagonal interactions.
关键词： exact-diagonalization method,honeycomb-lattice magnet,α-RuCl3,THz spectra,Heisenberg interaction,Kitaev interaction
更新于2025-09-23 15:21:21
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Optical Properties of Buckled Bismuthene
摘要： In this paper, the optical properties of buckled bismuthene (a new 2D material) are studied in different strains. Different transitions in bismuthene’s band structure are mentioned and the optical advantages of buckled bismuthene are discussed. It is found that buckled bismuthene is strain independent infrared (IR) reducer and could be used in bio photonics.
关键词： 2D material,optical properties,reflection,group V monolayers,honeycomb lattice,absorption spectra,density functional theory,dielectric function,buckled bismuthene
更新于2025-09-11 14:15:04
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Correlations and electronic order in a two-orbital honeycomb lattice model for twisted bilayer graphene
摘要： The recent observation of superconductivity in proximity to an insulating phase in twisted bilayer graphene (TBG) at small “magic” twist angles has been linked to the existence of nearly ?at bands, which make TBG a fresh playground to investigate the interplay between correlations and superconductivity. The low-energy narrow bands were shown to be well described by an effective tight-binding model on the honeycomb lattice (the dual of the triangular Moiré superlattice) with a local orbital degree of freedom. In this paper, we perform a strong-coupling analysis of the proposed (px, py ) two-orbital extended Hubbard model on the honeycomb lattice. By decomposing the interacting terms in the particle-particle and particle-hole channels, we classify the different possible superconducting, magnetic, and charge instabilities of the system. In the pairing case, we pay particular attention to the two-component (d-wave) pairing channels, which admit vestigial phases with nematic or chiral orders, and study their phenomenology. Furthermore, we explore the strong-coupling regime by obtaining a simpli?ed spin-orbital exchange model which may describe a putative Mott-type insulating state at quarter-?lling. Our mean-?eld solution reveals a rich intertwinement between ferromagnetic and antiferromagnetic orders with different types of nematic and magnetic orbital orders. Overall, our work provides a solid framework for further investigations of the phase diagram of the two-orbital extended Hubbard model in both strong- and weak-coupling regimes.
关键词： spin-orbital exchange model,Hubbard model,twisted bilayer graphene,superconductivity,honeycomb lattice,correlations
更新于2025-09-09 09:28:46