The Electronic Structure and Optical Properties of GeSe 2 : A First‐Principles Study

The continuous advancement of optoelectronic functional material technology has sparked increasing interest in the IV–VI compound GeSe 2 , attributed to its unique structure and remarkable optoelectronic properties. GeSe 2 is known to form seven distinct spatial symmetry structures, each exhibiting varying electronic and physical characteristics. The electronic and physical properties of these different structures are systematically studied using first‐principles methods, and the results showed that there are significant differences in the electronic structure and optical properties exhibited by GeSe 2 with different structures. Among them, GeSe 2 with I ‐ 4 , I41 , and P42 phase structures exhibits metallic properties, while GeSe 2 with I42D , P3m1 , P ‐ 4 , and P21 phase structures exhibits semiconductor properties. Notably, the I42D and P ‐ 4 structures demonstrate pronounced light absorption in the ultraviolet (UV) region, suggesting potential applications in UV detectors and light‐emitting devices. Mulliken population analysis further indicates that there are significant differences in electron distribution and charge transfer between Ge and Se atoms in GeSe 2 with different phase structures, especially in the I42D , P3m1 , P‐4 , and P21 phase structures exhibiting semiconductor behavior, and the mechanisms of charge transfer and electron transitions clarify the changes in the energy‐band structure.