AI 中文总结
本文利用DFT和HSE06方法系统研究了T-GaN单层的结构、力学、电子和光学性质，发现其具有动力学稳定性、面内各向异性和间接带隙，可作为各向异性纳米电子和光电子应用的候选材料。
AI 中文摘要
对非六方二维拓扑结构的探索为调控III-V族单层材料的性质开辟了新的可能性，超越了传统蜂窝状相所能实现的范围。在此背景下，我们利用广义梯度近似（GGA/PBE）和杂化HSE06泛函的密度泛函理论（DFT），研究了T-GaN的结构、力学、电子和光学性质。T-GaN是一种二维四方氮化镓单层，由交替的四元环和八元环组成，具有共存的同元素（Ga-Ga、N-N）和异极（Ga-N）键。声子色散计算证实了T-GaN的动力学稳定性，在整个布里渊区未发现虚频，并进一步得到了从头算分子动力学（AIMD）模拟的支持。力学表征揭示了显著的面内各向异性，沿x和y方向的临界应变分别约为16.5%和7.0%。电子能带结构分析表明，T-GaN是一种非磁性半导体，间接带隙为0.35 eV（PBE）和1.15 eV（HSE06），价带最大值主要由氮2p轨道主导，导带最小值由镓4s和4p态控制。沿三个晶向评估了光学响应，吸收系数、折射率和反射率表现出显著的各向异性。这些发现为四方III-V族单层材料的物理性质提供了新的见解，并表明T-GaN可能成为各向异性纳米电子和光电子应用的有前景候选材料。
英文摘要
The exploration of non-hexagonal two-dimensional topologies has opened new possibilities for tailoring the properties of group III-V monolayers beyond those accessible through conventional honeycomb phases. In this context, we have investigated the structural, mechanical, electronic, and optical properties of T-GaN, a two-dimensional tetragonal gallium nitride monolayer composed of alternating four- and eight-membered rings featuring coexisting homoelemental (Ga-Ga, N-N) and heteropolar (Ga-N) bonds, using density functional theory (DFT) within the generalized gradient approximation (GGA/PBE) and the hybrid HSE06 functional. The dynamical stability of T-GaN was confirmed by phonon dispersion calculations, which revealed the absence of imaginary frequencies throughout the Brillouin zone, and was further supported by \textit{ab initio} molecular dynamics (AIMD) simulations. The mechanical characterization reveals a pronounced in-plane anisotropy, with critical strains of approximately 16.5\% and 7.0\% along the $x$- and $y$-directions, respectively. The electronic band structure analysis indicates that T-GaN is a nonmagnetic semiconductor with an indirect band gap of 0.35~eV (PBE) and 1.15~eV (HSE06), with the valence band maximum dominated by nitrogen 2\textit{p} orbitals and the conduction band minimum governed by gallium 4\textit{s} and 4\textit{p} states. The optical response was evaluated along three crystallographic directions, exhibiting considerable anisotropy in the absorption coefficient, refractive index, and reflectivity. These findings provide new insights into the physical properties of tetragonal group III-V monolayers and suggest that T-GaN may serve as a promising candidate for anisotropic nanoelectronic and optoelectronic applications.
Comments13 pages and 8 figures
