Topological electronic structure in half-Heusler topological insulators

W. Al-Sawai, Northeastern University
Hsin Lin, Northeastern University
R. S. Markiewicz, Northeastern University
L. A. Wray, Princeton University
Y. Xia, Princeton University
S. Y. Xu, Princeton University
M. Z. Hasan, Princeton University
A. Bansil, Northeastern University

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Originally published in Physical Review B v.82 (2010): 125208. DOI: 10.1103/PhysRevB.82.125208

Abstract

We have investigated band structures of a series of 28 ternary half-Heusler compounds MM'X of MgAgAs type, where M=(Lu, La, Sc, Y) and M'X=(PtBi, AuPb, PdBi, PtSb, AuSn, NiBi, PdSb). Our results show that the Z₂ topological order is due to a single band inversion at the Γ point. In native states, these half-Heusler compounds are identified as being topologically nontrivial semimetals, or nontrivial metals, or trivial insulators, which can be turned into insulating thin films on suitable substrates. Our analysis reveals a straightforward relationship which connects the band inversion strength (extent of deviation from the critical point) to the atomic charge of constituents and the lattice parameter. Our findings suggest a general method for identifying Z₂ topological insulators in nonmagnetic ternary compounds.