Bilinear magnetoresistance in topological insulators: The role of spin–orbit scattering on impurities

Bilinear magnetoresistance (BMR) is a new kind of magnetoresistance, that scales linearly with electric and magnetic fields. This magnetoresistance occurs in systems with strong spin–orbit interaction. Additionally, this interaction also leads to quadratic magnetoresistance (QMR). We consider theoretically BMR and QMR in surface states of 3D topological insulators, and propose a new mechanism that leads to these effects. This mechanism is based on scattering on spin–orbit impurities. Accordingly, we assume the minimal model of surface electronic states in a single independent surface of a TI, and calculate both BMR and QMR induced as an interplay of current-induced spin polarization (or equivalently effective spin–orbit field) and spin–orbit scattering on impurities. We present detailed characteristics of both BMR and QMR, and compare our results with those obtained for TIs with spin-momentum locking inhomogeneities and hexagonal warping of the Dirac cones.