Abstract
It has been proposed that adding disorder to a topologically trivial mercury telluride/cadmium telluride (HgTe/CdTe) quantum well can induce a transition to a topologically nontrivial state. The resulting state was termed topological Anderson insulator and was found in computer simulations of the Bernevig-Hughes-Zhang model. Here, we show that the topological Anderson insulator is a more universal phenomenon and also appears in the Kane-Mele model of topological insulators on a honeycomb lattice. We numerically investigate the interplay of the relevant parameters, and establish the parameter range in which the topological Anderson insulator exists. A staggered sublattice potential turns out to be a necessary condition for the transition to the topological Anderson insulator. For weak enough disorder, a calculation based on the lowest-order Born approximation reproduces quantitatively the numerical data. Our results thus considerably increase the number of candidate materials for the topological Anderson insulator phase.
Highlights
It has been proposed that adding disorder to a topologically trivial mercury telluride/cadmium telluride (HgTe/CdTe) quantum well can induce a transition to a topologically nontrivial state
I ci† c i, i which has been supplemented by an on-site Anderson disorder term with disorder strength W and uniformly disntreibiguhtbedorrsaannddomnevxat-rniaebalreess tin∈eig[h−b1o,r1s,].rTeshpeescutimvemlya. tTiohnesoopveerrattohreslcai†tti=ce(scii†t↑e,sc〈i†↓ i)j,〉c ai n=d
The Wannier states at the two basis atoms of the honeycomb lattice are separated in energy by twice the staggered sublattice potential λν, with ξi = 1 for the A sublattice and ξi = −1 for the B sublattice
Summary
It has been proposed that adding disorder to a topologically trivial mercury telluride/cadmium telluride (HgTe/CdTe) quantum well can induce a transition to a topologically nontrivial state. The most prominent 2D TIs are HgTe/(Hg, Cd)Te quantum wells (HgTeQWs)[6] and InAs/GaSb heterostructures[7,8], whereas 3D TIs were found for instance in Bi1−xSbx[9] The fact that their metallic surface states emerge due to a topological property of the bulk band structure means that they are robust to weak disorder. It was predicted that the opposite transition can happen in certain parameter ranges: adding strong disorder can convert a trivial insulator without edge states into a topological insulator with perfectly conducting edge states. Materials that exhibit this new state have been termed topological Anderson insulators (TAIs). For even stronger W, above the disorder strength at which the states of the conduction and valence band localize, it was proposed that tunneling across the bulk becomes possible[13], probably enabled by percolating states[14], and the conductance is again suppressed
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