Quantum Dot Spin Filter in Resonant Tunneling and Kondo Regimes
Quantum Dot Spin Filter in Resonant Tunneling and Kondo Regimes
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DOI：
10.1143/jpsj.79.123711
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发表时间：
2010-10
影响因子：
1.7
通讯作者：
M. Eto;T. Yokoyama
中科院分区：
文献类型：
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作者：
M. Eto;T. Yokoyama
如果具有自旋轨道相互作用的量子点通过隧道势垒连接到 N (≥3) 个外部引线，则它可以用作高效的自旋过滤器。当非极化电流从引线注入量子点时，极化电流被喷射到其他引线。将两级量子点作为最小模型进行检查。首先，我们表明，当点中的能级间距小于能级展宽时，自旋极化通过共振隧道显着增强。接下来，我们研究库仑封锁状态下近藤效应引起的多体共振。当能级间距小于近藤温度时，在 SU(4) 近藤效应的存在下会产生大的自旋电流。
A quantum dot with spin–orbit interaction can work as an efficient spin filter if it is connected to N (≥3) external leads via tunnel barriers. When an unpolarized current is injected to a quantum dot from a lead, polarized currents are ejected to other leads. A two-level quantum dot is examined as a minimal model. First, we show that the spin polarization is markedly enhanced by resonant tunneling when the level spacing in the dot is smaller than the level broadening. Next, we examine the many-body resonance induced by the Kondo effect in the Coulomb blockade regime. A large spin current is generated in the presence of the SU(4) Kondo effect when the level spacing is less than the Kondo temperature.