Alternating response of spin current in a magnetic-oscillating quantum dot
We investigate alternating response of the spin current in a quantum dot system coupled to a normal metal electrode, to which an alternating driving voltage and a pumping rotating magnetic field are applied. The expression of the time-averaged spin current and its differential is obtained based on a non-equilibrium Green's function method. We find that for a given rotating frequency, the spin current increases rapidly and appears to have small steps when the driven frequency increases. As the driven frequency is further increasing, the spin current can be significantly enhanced and approaches a stable value. The photon-assisted processes bring about interesting features of spin current. The influence of the gate voltage and temperature on the spin current is examined in detail.
spin current, AC response, photon-assisted tunneling.
宋红岩、宋小龙、张爱芳、吴留坡、施耀铭
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Department of Physics, College of Sciences, Shanghai University, Shanghai 200444, P. R. China
spin current, AC response, photon-assisted tunneling.
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