Temperature-Dependent Angle-Resolved Photoemission Spectra of TlInSe₂: Manifestations of Incommensurate and Commensurate Phases

Abstract

The energy band structures of the valence band of the TlInSe2 material with a quasi one-dimensional chain structure and a giant Seebeck coefficient at temperatures below 413 K were investigated by angle-resolved photoemission spectroscopy at 280 and 50 K. The obtained energy bands and the calculated band structure were found to correspond well in main futures. A detailed analysis using both experimental and theoretical data was performed and the obtained results were evident of the presence of the incommensurate phase linked to a certain point on the A line of the Brillouin zone of TlInSe2. A self-consistent picture of the phase transition in TlInSe2 was drawn after discussion using available data for this material. According to this picture, TlInSe2 at 50 K is already a commensurate material while the incommensurate-commensurate phase transition occurs between 280 and 50 K.