Stacked topological insulator built from bismuth-based graphene sheet analogues

Abstract

Commonly materials are classified as either electrical conductors or insulators. The theoretical discovery of topological insulators (TIs) in 2005 has fundamentally challenged this dichotomy. In a TI, spin-orbit interaction generates a non-trivial topology of the electronic band-structure dictating that its bulk is perfectly insulating, while its surface is fully conducting. The first TI candidate material put forward -graphene- is of limited practical use since its weak spin-orbit interactions produce a band-gap of ~0.01K. Recent reinvestigation of Bi2Se3 and Bi2Te3, however, have firmly categorized these materials as strong three-dimensional TI's. We have synthesized the first bulk material belonging to an entirely different, weak, topological class, built from stacks of two-dimensional TI's: Bi14Rh3I9. Its Bi-Rh sheets are graphene analogs, but with a honeycomb net composed of RhBi8-cubes rather than carbon atoms. The strong bismuth-related spin-orbit interaction renders each graphene-like layer a TI with a 2400K band-gap.

10 pages, 3 figures

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Cited by in corpus (12)

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• Bulk characterization of topological crystalline insulators: stability under interactions and relations to symmetry enriched U(1) quantum spin liquids
• Characterizing the weak topological properties: Berry phase point of view
• Effects of Defects and Dephasing on Charge and Spin Currents in Two-Dimensional Topological Insulators
• Spin- and angle-resolved photoemission on the topological Kondo Insulator candidate: SmB6
• BaSn${}_2$: A new, wide-gap, strong topological insulator
• Topological spin liquids in the ruby lattice with anisotropic Kitaev interactions
• One-dimensional Dirac electrons on the surface of weak topological insulators
• Delocalization of surface Dirac electrons in disordered weak topological insulators
• Effective model for massless Dirac electrons on a surface of weak topological insulators
• Chemical Gating of a Weak Topological Insulator: Bi14Rh3I9
• Engineering Dirac electrons emergent on the surface of a topological insulator