Quantum spin Hall phase in 2D trigonal lattice.
The quantum spin Hall (QSH) phase is an exotic phenomena in condensed-matter physics. Here we show that a minimal basis of three orbitals (s, px, py) is required to produce a QSH phase via nearest-neighbour hopping in a two-dimensional trigonal lattice. Tight-binding model analyses and calculations show that the QSH phase arises from a spin-orbit coupling (SOC)-induced s-p band inversion or p-p bandgap opening at Brillouin zone centre (Γ point), whose topological phase diagram is mapped out in the parameter space of orbital energy and SOC. Remarkably, based on first-principles calculations, this exact model of QSH phase is shown to be realizable in an experimental system of Au/GaAs(111) surface with an SOC gap of ∼73 meV, facilitating the possible room-temperature measurement. Our results will extend the search for substrate supported QSH materials to new lattice and orbital types.
Hefei National Laboratory for Physical Sciences at the Microscale, Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.|Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah 84112, USA.
Z F
ZF
Wang
Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah 84112, USA.
Kyung-Hwan
KH
Jin
Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah 84112, USA.|Collaborative Innovation Center of Quantum Matter, Beijing 100084, China.
Feng
F
Liu