Spin Filter Based on an Aharonov--Bohm Interferometer with Rashba Spin--Orbit Effect
FANG Ming1, SUN Lian-Liang2
1Department of Physics and Institute of Graduate Students, Bohai University, Jinzhou 1210002College of Science, North China University of Technology, Beijing 100041
Spin Filter Based on an Aharonov--Bohm Interferometer with Rashba Spin--Orbit Effect
FANG Ming1, SUN Lian-Liang2
1Department of Physics and Institute of Graduate Students, Bohai University, Jinzhou 1210002College of Science, North China University of Technology, Beijing 100041
摘要We propose a spin filter based on both the quantum interference and the Rashba spin--orbit (RSO) effects. This spin filter consists of a Aharonov--Bohm (AB) interferometer with two quantum dots (QDs) inserted in its arms. The influences of a magnetic flux φ threading through the AB ring and the RSO interaction inside the two QDs are taken into account by using the nonequilibrium Green's function technique. Due to the existence of the RSO interaction, the electrons flowing through different arms of the ring will acquire a spin-dependent phase factor in the linewidth matrix elements. This phase factor, combined with the influence of the magnetic flux, will induce a spin-dependent electron transport through the device. Moreover, we show that by tuning the magnetic flux, the RSO strength and the inter-dot tunnelling coupling strength, a pure spin-up or spin-down conductance can be obtained when a spin-unpolarized current is injected from the external leads, which can be used to filter the electron spin.
Abstract：We propose a spin filter based on both the quantum interference and the Rashba spin--orbit (RSO) effects. This spin filter consists of a Aharonov--Bohm (AB) interferometer with two quantum dots (QDs) inserted in its arms. The influences of a magnetic flux φ threading through the AB ring and the RSO interaction inside the two QDs are taken into account by using the nonequilibrium Green's function technique. Due to the existence of the RSO interaction, the electrons flowing through different arms of the ring will acquire a spin-dependent phase factor in the linewidth matrix elements. This phase factor, combined with the influence of the magnetic flux, will induce a spin-dependent electron transport through the device. Moreover, we show that by tuning the magnetic flux, the RSO strength and the inter-dot tunnelling coupling strength, a pure spin-up or spin-down conductance can be obtained when a spin-unpolarized current is injected from the external leads, which can be used to filter the electron spin.
FANG Ming; SUN Lian-Liang. Spin Filter Based on an Aharonov--Bohm Interferometer with Rashba Spin--Orbit Effect[J]. 中国物理快报, 2008, 25(9): 3389-3392.
FANG Ming, SUN Lian-Liang. Spin Filter Based on an Aharonov--Bohm Interferometer with Rashba Spin--Orbit Effect. Chin. Phys. Lett., 2008, 25(9): 3389-3392.
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2008, Vol. 25 
