关键词: Bi₂WO₆, 单轴应变, 电子性质, 第一性原理计算, 力学性质

Abstract:

Band structure， electronic density of states， mechanical properties， and carrier effective mass of Bi₂WO₆ were systematically calculated using first-principles density functional theory. The influence of uniaxial strain applied along the x， y， and z directions on the material’s band structure and the effective mass of generated carriers was thoroughly investigated. The results demonstrate that the calculated elastic constants reveal strong mechanical stability of Bi₂WO₆， along with pronounced anisotropic behavior. The band structure calculations reveal that Bi₂WO₆ is an indirect bandgap semiconductor with a bandgap of 2.422 eV. Under uniaxial strain， the bandgap exhibits tunability， with the maximum variation observed along the x direction. Upon strain application， the electronic bandgap of Bi₂WO₆ can be modulated within the range of 1.851 eV to 2.796 eV. In addition， the effective mass of charge carriers in Bi₂WO₆ can be precisely modulated by applied strain. The disparity between electron and hole effective masses increases markedly with increasing uniaxial tensile strain， thereby significantly promoting the spatial separation of generated electron-hole pairs. This behavior is well consistent with experimental observations showing enhanced pizeocatalytic activity of Bi₂WO₆ powder under strong mechanical stress. This study provides a theoretical foundation for gaining deeper insight into the intrinsic coupling between mechanical strain， band structure， and catalytic activity in piezoelectric catalytic materials.

Key words: Bi₂WO₆, uniaxial strain, electronic property, first-principles calculation, mechanical property