Charge transport in magnetic topological ultra-thin films: the effect of structural inversion asymmetry

Abstract

We study the effect of structural inversion asymmetry, induced by the presence of substrates or by external electric fields, on charge transport in magnetic topological ultra-thin films. We consider general orientations of the magnetic impurities. Our results are based on the Boltzmann formalism along with a modified relaxation time scheme. We show that the structural inversion asymmetry enhances the charge transport anisotropy induced by the magnetic impurities and when only one conduction subband contributes to the charge transport a dissipationless charge current is accessible. We demonstrate how a substrate or gate voltage can control the effect of the magnetic impurities on the charge transport, and how this depends on the orientation of the magnetic impurities.

Axion insulator states in a topological insulator proximitized to magnetic insulators: A tight-binding characterization

“…where v F is the Fermi velocity, ∆ m = ∆ h + Bk 2 represents the coupling between the top and bottom states and ∆ h denotes the coupling gap at the surfaces 26,27 . In the three-dimensional topological insulators family of Bi 2 Se 3 , the bulk samples have a gap, while the surface states are gapless and contain a Dirac cone.…”