Electronic structure of the high-temperature tetragonal Tl3PbBr5 phase

Abstract We report on calculations of total and partial densities of states of atoms constituting the high-temperature (HT) tetragonal Tl 3 PbBr 5 phase (space group P 4 1 ) using the full potential linearized augmented plane wave (FP-LAPW) method. Our theoretical data reveal that the tetragonal HT -Tl 3 PbBr 5 phase is an indirect-gap material with band gap of 2.26 eV. In addition, the FP-LAPW calculations render that dominant contributors in the valence-band region of HT -Tl 3 PbBr 5 are the Br 4p-like states, which contribute mainly into the top and the central portion of the valence band with also significant contributions throughout the whole valence-band region. The main contributors to the bottom of the valence band of the HT -Tl 3 PbBr 5 phase are the Tl 6s-like states, whilst the unoccupied Pb 6p-like states dominate at the bottom of the conduction band. The X-ray photoelectron core-level and valence-band spectra for the HT -Tl 3 PbBr 5 phase have been measured and compared with those of previously studied the low-temperature orthorhombic Tl 3 PbBr 5 phase.