The electronic structure of CsSnBr3 and related trihalides; Studies using XPS and band theory

The electronic structure of the cubic phase of crystalline CsSnBr3 has been investigated using X-ray photoelectron spectroscopy and a semiempirical energy band structure calculation. The observed semimetallic behaviour of this system and some similar crystalline trihalides in the cubic phase is related to the presence of a triply degenerate R15 energy level in the calculated conduction band. The nonmetallic behaviour of the cubic phase of CsSnCl3 may be accounted for by consideration of the spin-orbit splitting of this R15 level.