This paper investigates strain effects on the electronic and optical properties of monolayer GaSe using first-principles calculations. The geometric deformation significantly alters energy dispersion, band gap, and the band edge states of GaSe. The band gap evolution exhibits both linearly and nonlinearly with the strains and is strongly dependent on the types of deformation and the direction of the modifications. The external mechanical strains also significantly tailor the optical properties of GaSe, the exciton binding energy is strongly reduced when the tensile strain is applied, while the opposite way is true for compressive stress. Moreover, the inhomogeneous strain also induces a nonuniform electronic screening environment and strong polarization in the absorption spectra. The calculations demonstrate that the electronic and optical properties of GaSe monolayer can be significantly tuned by using strain engineering which appears as a promising way to design novel optoelectronic devices.

中文翻译：

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通过应变调节单层 GaSe 的电子和光学特性

本文利用第一性原理计算研究了应变对单层 GaSe 电子和光学特性的影响。几何变形显着改变了 GaSe 的能量色散、带隙和能带边缘状态。带隙演化与应变呈现线性和非线性关系，并且强烈依赖于变形类型和修改方向。外部机械应变也显着地改变了 GaSe 的光学特性，当施加拉伸应变时，激子结合能大大降低，而对于压缩应力则相反。此外，不均匀的应变还导致不均匀的电子屏蔽环境和吸收光谱中的强偏振。