Berlin 2012 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 30: Functional Materials III
MM 30.3: Vortrag
Mittwoch, 28. März 2012, 10:45–11:00, H 0106
Intrinsic point defects in ZnSb — Lasse Bjerg1, •Georg K. H. Madsen2, and Bo B. Iversen1 — 1Department of Chemistry & iNANO, Aarhus University, Denmark — 2Department of Atomistic Modelling and Simulation, ICAMS, Ruhr-Universität Bochum, Germany
Several efficient thermoelectric materials have been found among the ternary Zintl antimonides. If the band structure is highly asymmetric around the band gap, the efficiency as either n- or p-type may differ significantly. The Zintl antimonides have generally been found to be p-type. Surprising this also holds true for the narrow band gap binary ZnSb and Zn4Sb3.
Using ab initio calculations we investigate intrinsic point defects in ZnSb as a possible origin of the p-type conductivity. Negatively charged Zn vacancies are found to have a low formation energy, leading to an intrinsic p-type behavior. We discuss this finding as a general explanation of p-type conductivity in Zintl antimonides and how to overcome the doping limits in these materials.