Nanomagnet coupled to quantum spin Hall edge: An adiabatic quantum motor (Reprinted)

作者：Arrachea Liliana; von Oppen Felix^*

来源：Physica E: Low-Dimensional Systems and Nanostructures , 2016, 82: 247-253.

DOI：10.1016/j.physe.2016.02.037

• Quantum spin Hall effect
• Topological insulators
• Magnetization dynamics

The precessing magnetization of a magnetic islands coupled to a quantum spin Hall edge pumps charge along the edge. Conversely, a bias voltage applied to the edge makes the magnetization precess. We point out that this device realizes an adiabatic quantum motor and discuss the efficiency of its operation based on a scattering matrix approach akin to Landauer-Bfittiker theory. Scattering theory provides a microscopic derivation of the Landau-Lifshitz-Gilbert equation for the magnetization dynamics of the device, including spin-transfer torque, Gilbert damping, and Langevin torque. We find that the device can be viewed as a Thouless motor, attaining unit efficiency when the chemical potential of the edge states falls into the magnetization-induced gap. For more general parameters, we characterize the device by means of a figure of merit analogous to the ZT value in thermoelectrics.

• 出版日期2016-8