First-principles study of structural phase transitions in CsSnI3

CsSnI3 has been recently identified as a potential perovskite semiconductor compound for optoelectronic device applications. It is clearly of great importance to understand synthetic pathways starting from material precursors through studying its structural phase transitions. By constraining the regularity of SnI6 octahedra during the phase transitions, the landscape of ground state energy is being mapped out. The coordinate parameters for the undistorted alpha and distorted beta and gamma structures at zero temperature are identified and compared with available experimental data. It is predicted that the alpha structure is instable at any temperature and acts merely as an intermediate state while the beta and gamma structures are stable ones, and they can be transformed reversibly. The role of Cs atoms played for phase transitions is also investigated. (C) 2013 AIP Publishing LLC.