Model Hamiltonian for topological insulators

Topological order parameters for interacting topological insulators.

We propose a topological order parameter for interacting topological insulators, expressed in terms of the full Green's functions of the interacting system. We show that it is exactly quantized for a time-reversal invariant topological insulator, and it can be experimentally measured through the topological magneto-electric effect. This topological order parameter can be applied to both interac...

Topological insulators

Floquet topological insulators for sound

The unique conduction properties of condensed matter systems with topological order have recently inspired a quest for the similar effects in classical wave phenomena. Acoustic topological insulators, in particular, hold the promise to revolutionize our ability to control sound, allowing for large isolation in the bulk and broadband one-way transport along their edges, with topological immunity...

Smooth gauge for topological insulators

We develop a technique for constructing Bloch-like functions for 2D Z2 insulators (i.e., quantum spinHall insulators) that are smooth functions of k on the entire Brillouin-zone torus. As the initial step, the occupied subspace of the insulator is decomposed into a direct sum of two “Chern bands,” that is, topologically nontrivial subspaces with opposite Chern numbers. This decomposition remain...

Topological crystalline insulators.

The recent discovery of topological insulators has revived interest in the band topology of insulators. In this Letter, we extend the topological classification of band structures to include certain crystal point group symmetry. We find a class of three-dimensional "topological crystalline insulators" which have metallic surface states with quadratic band degeneracy on high symmetry crystal sur...