Magnetotransport in a second-order topological insulator

The most salient feature distinguishing topological insulators from ordinary band insulators is their bulk-boundary correspondence: the topologically-nontrival nature of a bulk sample is signalled by the presence of protected gap-crossing electronic states, localized to the boundary of the sample. Higher-order topological insulators exhibit a somewhat more subtle bulk-boundary correspondence. They still possess protected gap-crossing states, but these are localized to a particular submanifold of the boundary. In the case of a three-dimensional, second-order topological insulator (SOTI), the protected states are localized to the one-dimensional "hinges" of a rectangular nanowire

We theoretically examine the effects of an applied magnetic field in a model of an SOTI, considering the case where the field couples to the orbital electronic motion. Based on numerical calculations, we predict a clear magnetotransport signature reflecting the interplay between Landau level physics and the hinge modes of the SOTI.