Valence band study of thermoelectric Zintl-phase SrZn_2Sb_2 and YbZn_2Sb_2: X-ray photoelectron spectroscopy and density functional theory
The electronic structure of SrZn_2Sb_2 and YbZn_2Sb_2 is investigated using density functional theory and high-resolution x-ray photoemission spectroscopy. Both traditional Perdew-Burke-Ernzerhof and state-of-the-art hybrid Heyd-Scuseria-Ernzerhof functionals have been employed to highlight the importance of proper treatment of exchange-dependent Zn 3d states, Yb 4f states, and band gaps. The role of spin-orbit corrections in light of first-principles transport calculations are discussed and previous claims of Yb^(3+) valence are investigated with the assistance of photoelectron as well as scanning and transmission electron microscopy.
Additional Information© 2010 The American Physical Society. Received 13 August 2009; revised manuscript received 15 March 2010; published 10 May 2010. Espen Flage–Larsen would like to thank the Norwegian Research Council for financial support and the NOTUR project for computational resources. Øystein Prytz would also like to thank the Norwegian Research Council for funding. In addition, we would like to thank Ole Martin Løvvik and Ole Bjørn Karlsen for discussions.
Published - FlageLarsen2010p10323Phys_Rev_B.pdf