Current response of a topological insulator to a static Zeeman field
Bor-Luen Huang1*, Sungkit Yip1
1Institute of Physics, Academia Sinica, Taipei, Taiwan
* presenting author:Bor-Luen Huang,

We study the magnetoelectric coupling at the surface of a topological insulator. We are in particular interested in the surface current induced by a static Zeeman/exchange field. For an insulator with zero Chern number, the boundary contribution is independent of the details at the boundary. With the appearance of surface states in the topological insulator, it is not immediately obvious if the response is not affected by the conditions at the surface. Using exact diagonalization to a lattice model, we demonstrate a significant cancelation between the Pauli and the Van-Vleck contribution. By applying a time-reversal symmetry-breaking term near the boundary to gap out the surface states, we still find no change in the surface current.

Keywords: topological insulator, spin-orbit coupling, magnetoelectric effect