Topological states in multi-orbital HgTe honeycomb lattices

Abstract

Research on graphene has revealed remarkable phenomena arising in the honeycomb lattice. However, the quantum spin Hall effect predicted at the K point could not be observed in graphene and other honeycomb structures of light elements due to an insufficiently strong spin-orbit coupling. Here we show theoretically that 2D honeycomb lattices of HgTe can combine the effects of the honeycomb geometry and strong spin-orbit coupling. The conduction bands, experimentally accessible via doping, can be described by a tight-binding lattice model as in graphene, but including multi-orbital degrees of freedom and spin-orbit coupling. This results in very large topological gaps (up to 35 meV) and a flattened band detached from the others. Owing to this flat band and the sizable Coulomb interaction, honeycomb structures of HgTe constitute a promising platform for the observation of a fractional Chern insulator or a fractional quantum spin Hall phase.

includes supplementary material

References in corpus (18)

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Cited by in corpus (7)

• p-band engineering in artificial electronic lattices
• Exciton Transfer in Array of Epitaxially Connected Nanocrystals
• Topological edge and corner states in Bi fractals on InSb
• Photonic Versus Electronic Quantum Anomalous Hall Effect
• Realization of a one-dimensional topological insulator in ultrathin germanene nanoribbons
• Tuning orbital-selective phase transitions in a two-dimensional Hund's correlated system
• Valley- and Orbital-Controlled 2D Chern Insulators Without Spin-orbit Interaction