Temperature-Driven Abrupt Changes in the Electronic Structure of 2D Si 2 Te 3 : A First-Principles Study

Si 2 Te 3 has emerged as a promising two-dimensional material due to its compatibility with existing silicon-based semiconductor processes, its intrinsic p-type conductivity, which is rare among 2D materials, and its potential for diverse applications. Recently, experimental studies have suggested that Si 2 Te 3 exhibits temperature-dependent changes in its optical and electrical properties. Although these observations are potentially linked to changes in Si–Si dimer orientations, the underlying mechanism remains unclear. Here, we employ first-principles density functional theory (DFT) calculations to investigate the impact of Si–Si dimer orientations on the electronic structure of Si 2 Te 3 . Our findings reveal that Si–Si dimer configurations can induce transitions between direct and indirect band gaps and significantly alter the hole effective mass. These results suggest a direct correlation between the orientations of Si–Si dimers and the resulting optical and electrical properties of Si 2 Te 3, providing new insights into the fundamental properties of Si 2 Te 3 and guiding future applications.