[en] 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.
Disciplines :
Physics
Author, co-author :
Beugeling, Wouter; Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Straße 38, 01187 Dresden, Germany
Kalesaki, Efterpi ; University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit
Delerue, Christophe; IEMN-Department ISEN, UMR CNRS 8520, 41 Boulevard Vauban, 59046 Lille, France
Niquet, Yann-Michel; Université Grenoble Alpes, INAC-SP2M, L_Sim, 17 avenue des Martyrs, 38054 Grenoble, France ; CEA, INAC-SP2M, L_Sim, 17 avenue des Martyrs, 38054 Grenoble, France
Vanmaekelbergh, Daniel; Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, The Netherlands
Morais Smith, Cristiane; Institute for Theoretical Physics, Center for Extreme Matter and Emergent Phenomena, Utrecht University, Leuvenlaan 4, 3584 CE Utrecht, The Netherlands
Language :
English
Title :
Topological states in multi-orbital HgTe honeycomb lattices