Strain effects on the electronic and optical properties of monolayer SnSe is studied by APW + lo method in DFT framework. The applied strains cause direct-indirect transition of SnSe band gap which is mainly constructed by $s/p$ hybridization. The armchair ${\epsilon }_{\mathit{ac}}$ and zigzag ${\epsilon }_{\mathit{zz}}$ reduce the unstrained band gap of 1.05 eV down to 0 eV at 12$\%$ compression, but at 12$\%$ tension, the band gap decreases to 0.726–0.804 eV. The band gap always increases under biaxial strain ${\epsilon }_b$ at at 12$\%$ compression to 12$\%$ tension. We observe an enhancement of real ${\epsilon }_1(\omega )$ and imaginary ${\epsilon }_2(\omega )$ parts of dielectric function by $14\%-30\%$ of magnitude, wider peak distribution to infrared and ultra-violet regions, and appearance of new peaks in the ${\epsilon }_1(\omega )$ and ${\epsilon }_2(\omega )$ spectrums. As a consequence, the light absorption $\alpha (\omega )$ is significantly enhanced in the ultra-violet region and the absorption even starts at lower energy at infrared region.

在DFT框架下，通过APW + lo方法研究了应变对单层SnSe电子和光学性能的影响。施加的应变会引起SnSe带隙的直接-间接跃迁，其主要结构如下：$s/p$杂交。扶手椅${\epsilon }_{\mathit{交流电}}$ 和之字形 ${\epsilon }_{\mathit{Z\; Z}}$ 将12时1.05 eV的无应变带隙降低至0 eV$％$ 压缩，但在12$％$张力下，带隙降低至0.726–0.804 eV。带隙总是在双轴应变下增加${\epsilon }_b$ 在12点$％$ 压缩到12$％$紧张。我们观察到真实的增强${\epsilon }_{\mathrm{1个}}（\omega ）$ 和虚构的 ${\epsilon }_{\mathrm{2个}}（\omega ）$ 介电功能部分 $14％--30％$ 数量级，在红外和紫外线区域的峰分布更宽，并且在色谱图中出现了新的峰 ${\epsilon }_{\mathrm{1个}}（\omega ）$ 和 ${\epsilon }_{\mathrm{2个}}（\omega ）$频谱。结果，光吸收$\alpha （\omega ）$ 在紫外光区域显着增强，吸收甚至在红外光区域以较低的能量开始。