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 ori...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.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61274101 and 51362031)the Initial Project for High-Level Talents of UESTC,Zhongshan Insitute,China(Grant No.415YKQ02)China Postdoctoral Science Foundation(Grant No.2014M562301)
文摘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.
基金supported by the National High Technology Research and Development Program of China(863)(2011AA050528)National Natural Science Foundation of China(51072232,21171175)~~
