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-Büttiker 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. © 2016.
Documento: | Artículo |
Título: | Reprint of: Nanomagnet coupled to quantum spin Hall edge: An adiabatic quantum motor |
Autor: | Arrachea, L.; von Oppen, F. |
Filiación: | Departamento de Física, FCEyN, Universidad de Buenos Aires and IFIBA, Pabellón I, Ciudad Universitaria, 1428 CABA, Argentina International Center for Advanced Studies, UNSAM, Campus Miguelete, 25 de Mayo y Francia, 1650 Buenos Aires, Argentina Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany |
Palabras clave: | Magnetization dynamics; Quantum spin Hall effect; Topological insulators; Efficiency; Magnetization; Spin dynamics; Spin Hall effect; Landau-Lifshitz-Gilbert equations; Magnetization dynamics; Quantum Spin hall effect; Quantum spin halls; Scattering matrix approach; Scattering theory; Spin transfer torque; Topological insulators; Quantum Hall effect |
Año: | 2015 |
Volumen: | 82 |
DOI: | http://dx.doi.org/10.1016/j.physe.2016.02.037 |
Título revista: | Physica E: Low-Dimensional Systems and Nanostructures |
Título revista abreviado: | Phys E |
ISSN: | 13869477 |
CODEN: | PELNF |
Registro: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_13869477_v82_n_p_Arrachea |