Abstract Based on density functional theory (DFT), the electronic and optical properties of PdSe2 from monolayer to trilayer are systematically studied. The 1.37eV indirect band gap of monolayer PdSe2 reflects its semiconductor behavior, and the band gap tends to decrease with the increase of the number of layers. The band gap of PdSe2 from monolayer to trilayer are basically consistent with the experimental values. The conduction band minimum (CBM) and valence band maximum (VBM) mostly come from the Pd-4d orbitals and Se-4p orbitals. Interestingly, two structures in the trilayer PdSe2 of ABA and ABB stackings show prominent light absorption, and their maximum light absorption values occur near the energy of 10.6eV in xx direction. The positions of absorption edge appear red shift with the increase of the number of layers in all directions. Additionally, the trilayers have high refractive index and reflectivity. From monolayer to trilayer, the static refractive index n (0) increases gradually. Therefore, they may have promising applications in optical coatings and tunable optoelectronic devices.

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PdSe2 从单层到三层的电子和光学性质

摘要 基于密度泛函理论(DFT)，系统地研究了PdSe2从单层到三层的电子和光学性质。单层PdSe2的1.37eV间接带隙反映了其半导体行为，带隙随着层数的增加而趋于减小。PdSe2 从单层到三层的带隙与实验值基本一致。导带最小值 (CBM) 和价带最大值 (VBM) 主要来自 Pd-4d 轨道和 Se-4p 轨道。有趣的是，ABA 和 ABB 堆叠的三层 PdSe2 中的两个结构表现出显着的光吸收，它们的最大光吸收值出现在 xx 方向的 10.6eV 能量附近。随着各个方向层数的增加，吸收边位置出现红移。此外，三层具有高折射率和反射率。从单层到三层，静态折射率 n (0) 逐渐增加。因此，它们可能在光学涂层和可调谐光电器件中具有广阔的应用前景。