Spin Caloritronics in III-V-Semiconductors

点击翻译按钮获取中文摘要

We propose to explore the potential of electrical and time-resolved optical methods for investigating heat-induced spin transport phenomena in III-V semiconductor heterostructures. In a first focus, we will generate coherent spin and charge packets by optical laser pulses. Their thermal conductivities shall be probed in a lateral temperature gradient by spatio-temporal measurements of time-resolved Faraday rotation (spin sensitive) and time-resolved transmission (charge sensitive). By generating initial spin directions parallel and perpendicular to the incident linearly polarized laser beam, we expect being able to explore the role of spin-orbit coupling for heat-induced spin transport. In a second focus, we propose to study whether, in analogy to a voltage gradient, a temperature gradient alone results in (I) a spin polarization or (II) a spin current. In (I), we study if a spin polarization will be created by internal magnetic fields, which are due to thermally-induced electric fields. In (II), we suggest to measure the spin- Nernst effect, for which a spin voltage is expected transverse to the direction of the thermal gradient. The spin voltage shall be measured either by magneto-optical probes or by electrical measurements of the photo-voltage or of the inverse spin Hall effect using platinum electrodes as detectors.