Topological Insulators in Ternary Compounds with a Honeycomb Lattice

Abstract

One of the most exciting subjects in solid state physics is a single layer of graphite which exhibits a variety of unconventional novel properties. The key feature of its electronic structure are linear dispersive bands which cross in a single point at the Fermi energy. This so-called Dirac cone is closely related to the surface states of the recently discovered topological insulators. The ternary compounds, such as LiAuSe and KHgSb with a honeycomb structure of their Au-Se and Hg-Sb layers feature band inversion very similar to HgTe which is a strong precondition for existence of the topological surface states. In contrast to graphene with two Dirac cones at K and K' points, these materials exhibit the surface states formed by only a single Dirac cone at the Γ-point together with the small direct band gap opened by a strong spin-orbit coupling (SOC) in the bulk. These materials are centro-symmetric, therefore, it is possible to determine the parity of their wave functions, and hence, their topological character. Surprisingly, the compound KHgSb with the strong SOC is topologically trivial, whereas LiAuSe is found to be a topological non-trivial insulator.

4 pages + 1 page supplemental

References in corpus (6)

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• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Topological Insulators with Inversion Symmetry
• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface
• Covalent bonding and the nature of band gaps in some half-Heusler compounds
• Searching for hexagonal analogues of the half-metallic half-Heusler XYZ compounds

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• Data Storage: Review of Heusler Compounds
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• Three-dimensional topological insulators: A review on host materials
• Generalized Slater-Pauling rule for the inverse Heusler compounds
• Prediction of topological insulating behavior in Hg2CuTi-type Heusler compounds from first principles
• Fabrication and characterization of the gapless half-Heusler YPtSb thin films