Thermoelectric effects in quantum Hall systems beyond linear response

27th International Conference on Low Temperature Physics

López, Rosa^1 ; Hwang, Sun-Yong^1 ; Sánchez, David^1

Institut de Física Interdisciplinària i de Sistemes Complexos IFISC (CSIC-UIB), Palma de Mallorca

E-07122, Spain^1

关键词: Antiparallel magnetizations;    Asymmetric transport;    Nonlinear dependence;    Parallel configuration;    Quantum Hall systems;    Temperature differences;    Topological insulators;    Wiedemann-Franz law;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/568/5/052016/pdf
DOI  :  10.1088/1742-6596/568/5/052016

来源: IOP

【 摘 要 】

We consider a quantum Hall system with an antidot acting as a energy dependent scatterer. In the purely charge case, we find deviations from the Wiedemann-Franz law that take place in the nonlinear regime of transport. We also discuss Peltier effects beyond linear response and describe both effects using magnetic-field asymmetric transport coefficients. For the spin case such as that arising along the helical edge states of a two-dimensional topological insulator, we investigate the generation of spin currents as a result of applied voltage and temperature differences in samples attached to ferromagnetic leads. We find that in the parallel configuration the spin current can be tuned with the leads' polarization even in the linear regime of transport. In contrast, for antiparallel magnetizations the spin currents has a strict nonlinear dependence on the the applied fields.