Quantization of interface currents

Motoko Kotani, Hermann Schulz-Baldes, Carlos Villegas-Blas

Published 2014-05-02, updated 2015-02-27Version 2

At the interface of two two-dimensional quantum systems, there may exist interface currents similar to edge currents in quantum Hall systems. It is proved that these interface currents are macroscopically quantized by an integer that is given by the difference of the Chern numbers of the two systems. It is also argued that at the interface between two time-reversal invariant systems with half-integer spin, one of which is trivial and the other non-trivial, there are dissipationless spin-polarized interface currents.