We theoretically studied the nonlocal Andreev reflection with Rashba spin-orbital interaction in a triple-quantumdot （QD） ring, which is introduced as Rashba spin-orbital interaction to act locally on one component ...We theoretically studied the nonlocal Andreev reflection with Rashba spin-orbital interaction in a triple-quantumdot （QD） ring, which is introduced as Rashba spin-orbital interaction to act locally on one component quantum dot. It is found that the electronic current and spin current are sensitive to the systematic parameters. The interdot spin-flip term does not play a leading role in causing electronic and spin currents. Otherwise the spin precessing terra leads to shift of the peaks of the the spin-up and spin-down electronic currents in different directions and results in the spin current. Moreover, the spin-orbital interaction suppresses the nonlocal Andreev reflection, so we cannot obtain the pure spin current.展开更多
This paper theoretically reports the nonlocal Andreev reflection and spin current in a normal metal-ferromagnetic metal-superconducting Aharonov-Bohm interferometer. It is found that the electronic current and spin cu...This paper theoretically reports the nonlocal Andreev reflection and spin current in a normal metal-ferromagnetic metal-superconducting Aharonov-Bohm interferometer. It is found that the electronic current and spin current are sensitive to systematic parameters, such as the gate voltage of quantum dots and the external magnetic flux. The electronic current in the normal metal lead results from two competing processes： quasiparticle transmission and nonlocal Andreev reflection. The appearance of zero spin-up electronic current （or spin-down electronic current） signals the existence of nonlocal Andreev reflection, and the presence of zero electronic current results in the appearance of pure spin current.展开更多
We extend the Blonder, Tinkham and Klapwijk theory to the study of the inverse proximity effects in the normal mental/superconductor/ferromagnet structures. In the superconducting film, there are the gapless supercond...We extend the Blonder, Tinkham and Klapwijk theory to the study of the inverse proximity effects in the normal mental/superconductor/ferromagnet structures. In the superconducting film, there are the gapless superconductivity and the spin-dependent density of states both within and without the energy gap. It indicates an appearance of the inverse-proximity-effect-induced ferromagnetism and a coexistence of ferromagnetism and superconductivity near the interface. The influence of exchange energy in the ferromagnet and barrier strength at the superconductor/ferromagnet interface on the inverse proximity effects is discussed.展开更多
The scattering matrix approach between the clean and dirty limits is developed for the study of tunnelling spectra in a ferromagnetic film in proximity to a superconductor. The minigap and the damped oscillation from ...The scattering matrix approach between the clean and dirty limits is developed for the study of tunnelling spectra in a ferromagnetic film in proximity to a superconductor. The minigap and the damped oscillation from ＇0＇ to ＇~＇ state in tunnelling conductance are attributed to the phase coherence of the electrons and the corresponding Andreev-reflected holes in the ferromagnetic film. The calculated results provide a reasonable explanation for the behaviour observed in recent experiments.展开更多
基金Project supported by the Natural Science Foundation of Education Bureau of Jiangsu Province of China (Grant Nos. 08KJB140002 and 09KJD430004)
文摘We theoretically studied the nonlocal Andreev reflection with Rashba spin-orbital interaction in a triple-quantumdot （QD） ring, which is introduced as Rashba spin-orbital interaction to act locally on one component quantum dot. It is found that the electronic current and spin current are sensitive to the systematic parameters. The interdot spin-flip term does not play a leading role in causing electronic and spin currents. Otherwise the spin precessing terra leads to shift of the peaks of the the spin-up and spin-down electronic currents in different directions and results in the spin current. Moreover, the spin-orbital interaction suppresses the nonlocal Andreev reflection, so we cannot obtain the pure spin current.
基金Project supported by the Special Funds of the National Natural Science Foundation of China (Grant Nos 10847133 and 10847132)the Natural Science Foundation of Education Bureau of Jiangsu Province,China (Grant No 08KJB140002)
文摘This paper theoretically reports the nonlocal Andreev reflection and spin current in a normal metal-ferromagnetic metal-superconducting Aharonov-Bohm interferometer. It is found that the electronic current and spin current are sensitive to systematic parameters, such as the gate voltage of quantum dots and the external magnetic flux. The electronic current in the normal metal lead results from two competing processes： quasiparticle transmission and nonlocal Andreev reflection. The appearance of zero spin-up electronic current （or spin-down electronic current） signals the existence of nonlocal Andreev reflection, and the presence of zero electronic current results in the appearance of pure spin current.
基金Project supported by the Special Funds of the National Natural Science Foundation of China(Grant Nos.10847132 and 10847133)the Natural Science Foundation of Education Bureau of Jiangsu Province,China(Grant No.07KJD140024)
文摘We extend the Blonder, Tinkham and Klapwijk theory to the study of the inverse proximity effects in the normal mental/superconductor/ferromagnet structures. In the superconducting film, there are the gapless superconductivity and the spin-dependent density of states both within and without the energy gap. It indicates an appearance of the inverse-proximity-effect-induced ferromagnetism and a coexistence of ferromagnetism and superconductivity near the interface. The influence of exchange energy in the ferromagnet and barrier strength at the superconductor/ferromagnet interface on the inverse proximity effects is discussed.
基金Project supported by the Natural Science Foundation of Education Bureau of Jiangsu Province, China (Grant No 07KJD140024)Jiangsu key Laboratory for Chemistry of Low-Dimensional Materials (Huaiyin Teachers College), China
文摘The scattering matrix approach between the clean and dirty limits is developed for the study of tunnelling spectra in a ferromagnetic film in proximity to a superconductor. The minigap and the damped oscillation from ＇0＇ to ＇~＇ state in tunnelling conductance are attributed to the phase coherence of the electrons and the corresponding Andreev-reflected holes in the ferromagnetic film. The calculated results provide a reasonable explanation for the behaviour observed in recent experiments.
