Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 51: Topological Insulators II (jointly with MA, DS, O, TT)

HL 51.5: Talk

Wednesday, March 28, 2012, 10:30–10:45, EB 301

Heusler topological insulators: Electronic structure and transport properties — •C. Shekhar¹, S. Ouardi², G. H. Fecher^{1, 2}, A. K. Nayak¹, A. Gloskovskii², E. Ikenaga³, S. Ueda⁴, K. Kobayashi⁴, and C. Felser^1,2 — ¹Max Planck Institute for Chemical Physics of Solids, Dresden — ²Institute of Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg - University, Mainz — ³Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo, Japan — ⁴National Institute for Materials Science, SPring-8, Hyogo, Japan

Topological insulators have a high potential for spintronics devices and quantum computation. Various Heusler compounds crystallize in a fcc structure of the C1_b type and consist of 2 transition metals and a main group element. If the compounds contain heavy metals and a lanthanide element then they exhibit extraordinary physical properties including superconductivity, half-metallic, semiconducting-like behavior, giant magnetoresistivity, heavy fermion state and zero band gap. The density of states of XMZ Heusler compounds (M = Gd, Lu, X= Au, Pt, Pd and Z= Pb, Sb, Bi) were investigated by hard X-ray photoelectron spectroscopy. The comparison of the experimental results to calculations gives evidence for the zero band gap state of the compounds. Further, the temperature dependence of electrical conductivity, magneto resistance, Hall mobility, Seebeck coefficient and thermal conductivity were investigated. The compounds exhibit a high Hall mobility and a linear magnetoresistance (MR). The observed linear MR is a quantum MR and due to the topological insulator state.