Electrically tunable spin polarization of chiral edge modes in a quantum anomalous Hall insulator

摘要

In the quantum anomalous Hall effect, chiral edge modes are expected toconduct spin polarized current without dissipation and thus hold great promisefor future electronics and spintronics with low energy consumption. However,spin polarization of chiral edge modes has never been established inexperiments. In this work, we theoretically study spin polarization of chiraledge modes in the quantum anomalous Hall effect, based on both the effectivemodel and more realistic tight-binding model constructed from the firstprinciples calculations. We find that spin polarization can be manipulated bytuning either a local gate voltage or the Fermi energy. We also propose toextract spin information of chiral edge modes by contacting the quantumanomalous Hall insulator to a ferromagnetic (FM) lead. The establishment ofspin polarization of chiral edge modes, as well as the manipulation anddetection in a fully electrical manner, will pave the way to the applicationsof the quantum anomalous Hall effect in spintronics.