%A Feng Chi(迟锋), Liming Liu(刘黎明), Lianliang Sun(孙连亮) %T Photon-mediated spin-polarized current in a quantum dot under thermal bias %0 Journal Article %D 2017 %J Chin. Phys. B %R 10.1088/1674-1056/26/3/037304 %P 37304-037304 %V 26 %N 3 %U {https://cpb.iphy.ac.cn/CN/abstract/article_119456.shtml} %8 2017-03-05 %X Spin-polarized current generated by thermal bias across a system composed of a quantum dot (QD) connected to metallic leads is studied in the presence of magnetic and photon fields. The current of a certain spin orientation vanishes when the dot level is aligned to the lead's chemical potential, resulting in a 100% spin-polarized current. The spin-resolved current also changes its sign at the two sides of the zero points. By tuning the system's parameters, spin-up and spin-down currents with equal strength may flow in opposite directions, which induces a pure spin current without the accompany of charge current. With the help of the thermal bias, both the strength and the direction of the spin-polarized current can be manipulated by tuning either the frequency or the intensity of the photon field, which is beyond the reach of the usual electric bias voltage.