Electrical manipulation of dynamic magnetic impurity and spin texture of helical Dirac fermions

¹ Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, ICMP and SPTE, South China Normal University - Guangzhou 510006, China
² Laboratory of Nanophotonic Functional Materials and Devices, South China Normal University Guangzhou 510006, China

Received: 16 March 2016
Accepted: 12 May 2016

Abstract

We have theoretically investigated the spin inelastic scattering of helical electrons off a high-spin nanomagnet absorbed on a topological surface. The nanomagnet is treated as a dynamic quantum spin and driven by the spin transfer torque effect. We proposed a mechanism to electrically manipulate the spin texture of helical Dirac fermions rather than by an external magnetic field. By tuning the bias voltage and the direction of impurity magnetization, we present rich patterns of spin texture, from which important fingerprints exclusively associated with the spin helical feature are obtained. Furthermore, it is found that the nonmagnetic potential can create the resonance state in the spin density with different physics as the previously reported resonance of charge density.