We study quantum transport phenomena in mesoscopic systems. Our interests include Anderson localization and transition, integer quantum (spin-) Hall effect, and transport properties in graphene nano-ribbons.

Topological insulators characterized by differences between bulk states and surface states respectively, which correspond to insulators and metallic states, are very hot fields of current research. We investigate the properties of three-dimensional topological insulators through numerical studies of current, local density of states and multifractality.