Atomic and electronic structure of cesium lead triiodide surfaces

The (001) surface of the emerging photovoltaic material cesium lead triiodide (CsPbI3 ) is studied. Using first-principles methods, we investigate atomic and electronic structure cubic ({\alpha}) orthorhombic ({\gamma}) CsPbI3 . For both phases, find that CsI-termination more stable than PbI2-termination. CsI-terminated surface, then compute analyse phase diagram. We observe surfaces with added or removed units nonpolar CsI PbI2 are most stable. corresponding band structures reveal {\alpha} exhibits states derive from conduction band. reconstructions do not introduce new in gap CsPbI3, but for additional at edge.