Electric response of a composite of topological insulator nanoparticles

Abstract

The electric response of a composite of topological insulator (TI) nanoparticles is studied using approximate effective medium models focusing on the topological magneto-electric (TME) response of the system. Both the Maxwell-Garnett and the Bruggeman models are generalized to incorporate the axion coupling parameter. Such a response is studied in the electrostatic limit via a capacitor with the composite as the dielectric medium. Manifestation of the TME is highlighted to provide an alternative probing method of such an effect via electrostatics experiments.