SU(3) topological insulators in the honeycomb lattice
Date of Issue2018
School of Physical and Mathematical Sciences
Institute of Advanced Studies
We investigate realizations of topological insulators with spin-1 bosons loaded in a honeycomb optical lattice and subjected to a SU ( 3 ) spin-orbit coupling—a situation which can be realized experimentally using cold atomic gases. In this paper, we focus on the topological properties of the single-particle band structure, namely, Chern numbers (lattice with periodic boundary conditions) and edge states (lattice with strip geometry) and their connection to time-reversal symmetry and the sublattice symmetry. While SU ( 2 ) spin-orbit couplings always lead to time-reversal symmetric tight-binding models, and thereby to topologically trivial band structures, suitable SU ( 3 ) spin-orbit couplings can break time-reversal symmetry and lead to topologically nontrivial bulk band structures and to edge states in the strip geometry. In addition, we show that one can trigger a series of topological transitions (i.e., integer changes of the Chern numbers) that are specific to the geometry of the honeycomb lattice by varying a single parameter in the Hamiltonian.
Physical Review A
© 2018 American Physical Society. All rights reserved. This paper was published in Physical Review A and is made available with permission of American Physical Society.