Giant magnetoresistance effect due to the tunneling between quantum anomalous Hall edge states

Abstract

A recent work predicted the tunneling effect between topological edge states where the tunneling probability is tuned by a transverse electric field [Xu et al., Phys. Rev. Lett. 123, 206801 (2019)]. Here we study this tunneling effect between quantum anomalous Hall edge states under a perpendicular magnetic field. It is shown that the tunneling probability depends exponentially on the magnetic field. We propose a magnetic transistor based on a quantum anomalous Hall ribbon to observe this effect experimentally. Numerical simulations show that the conductance of the device is very sensitive to the strength and direction of the magnetic field. The positive/negative magnetic field results in the on/off state of the transistor. A giant magnetoresistance is found, and the on/off ratio reaches up to greater than 1010 for a long ribbon. These findings should be useful for potential applications in magnetic read heads and magnetic field sensors.