TRIG-yne力学各向异性与应力调控研究

Study on the Mechanical Anisotropy and Stress Tuning of TRIG-yne

摘要: 本文采用第一性原理方法，研究了二维碳材料TRIG-yne的结构稳定性、力学各向异性及应力调控下的电子结构。结果表明，TRIG-yne的声子谱无虚频，内聚能与典型二维碳材料相近，结构稳定，其杨氏模量和泊松比表现出显著的各向异性。本征TRIG-yne为间接带隙半导体，费米能级附近的电子态主要由p轨道电子贡献。沿不同方向施加应力后，带隙变化趋势明显不同：x方向压缩使带隙减小、拉伸使带隙增大；y方向压缩对带隙影响较小，拉伸则使带隙闭合，体系转变为金属。相同大小的应力在不同方向上引起的电子结构变化明显不同，表明TRIG-yne的力学各向异性与电子特性之间存在显著耦合，其电子结构可通过应力方向和应力类型进行有效调控，为发展新型方向敏感电子器件提供了理论依据。

Abstract: In this work, the structural stability, mechanical anisotropy, and stress-tuned electronic structures of a two-dimensional carbon material, TRIG-yne, were investigated by first-principles calculations. The results show that TRIG-yne has no imaginary frequencies in its phonon spectrum and a cohesive energy comparable to those of typical two-dimensional carbon materials, indicating a stable structure, and its Young’s modulus and Poisson’s ratio exhibit pronounced anisotropy. Pristine TRIG-yne is an indirect bandgap semiconductor, and the electronic states near the Fermi level are mainly contributed by p orbitals. Under stresses applied along different directions, the bandgap variation shows distinctly different trends: compression along the x direction reduces the bandgap, while tension along the x direction enlarges it; compression along the y direction has little effect on the bandgap, whereas tension along the y direction closes the bandgap and drives the system into a metallic state. The significant differences in the electronic structure changes induced by the same magnitude of stress along different directions indicate a strong coupling between the mechanical anisotropy and electronic properties of TRIG-yne. These results suggest that the electronic structures of TRIG-yne can be effectively tuned by the stress direction and type, providing a theoretical basis for the development of novel direction-sensitive electronic devices.