Temperature‐dependent hard X‐ray photoemission spectra of ternary Tl compounds with high Seebeck coefficient

The temperature dependence of the core-level and valence-band electronic structures of TlGaTe2 and TlInSe2 that exhibits high values of Seebeck coefficient has been studied by hard X-ray photoemission spectroscopy over the temperature range 40–450 K. The relative peak position and peak width for Tl 4f, Ga 2p and Te 3d in TlGaTe2 are determined. It is shown that not only chemical shift defying the peak position but also electron-phonon interaction responsible for temperature line-broadening has rather peculiar temperature behaviour that reflects incommensurate phase transition. Thermoelectric power of TlGaTe2 is evaluated and found to be very close to that of TlInSe2. It is shown that Tl 4f spectra of both compounds also display close similarity (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)