paper

Magnetoelectric polarizability and axion electrodynamics in crystalline insulators

arXiv:0810.2998 · doi:10.1103/PhysRevLett.102.146805

Abstract

The orbital motion of electrons in a three-dimensional solid can generate a pseudoscalar magnetoelectric coupling , a fact we derive for the single-particle case using a recent theory of polarization in weakly inhomogeneous materials. This polarizability is the same parameter that appears in the "axion electrodynamics" Lagrangian , which is known to describe the unusual magnetoelectric properties of the three-dimensional topological insulator (). We compute for a simple model that accesses the topological insulator and discuss its connection to the surface Hall conductivity. The orbital magnetoelectric polarizability can be generalized to the many-particle wavefunction and defines the 3D topological insulator, like the IQHE, in terms of a topological ground-state response function.

4 pages; minor changes resulting from a change in one reference

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