耦合三端子量子点系统中Andreev反射调控的热电输运
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摘要
以耦合到超导电极、铁磁金属电极及正常金属电极的三端子量子点混杂系统为研究对象,系统研究了自旋极化电子的Andreev反射过程对热电流的影响.研究发现,Andreev反射过程及正常的隧穿过程2种机制的竞争不仅导致热电荷流大小和方向的改变,而且导致热自旋流大小和方向的改变.可通过调控门电压及超导体与量子点耦合强度实现.
The influence of spin-polarized electronic transports associated with Andreev reflection on the thermoelectric currents is investigated in a three-terminal hybridized system,consisting of an interacting quantum dot tunnel coupled to one superconducting,one ferromagnetic,and one normal lead.The numerical results show that the competition between the Andreev reflection and normal tunneling leads to the changes in the magnitude and direction of both thermal charge current and thermal spin current.Experimentally,it can be realized by modulating the gate voltage and the coupling strength between the superconducting lead and quantum dot.
The influence of spin-polarized electronic transports associated with Andreev reflection on the thermoelectric currents is investigated in a three-terminal hybridized system,consisting of an interacting quantum dot tunnel coupled to one superconducting,one ferromagnetic,and one normal lead.The numerical results show that the competition between the Andreev reflection and normal tunneling leads to the changes in the magnitude and direction of both thermal charge current and thermal spin current.Experimentally,it can be realized by modulating the gate voltage and the coupling strength between the superconducting lead and quantum dot.
引文
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[2]Wang R Q,Sheng L,Shen R,et al.Thermoelectric effect in single-molecule-magnet junctions[J].Physical Review Letters,2010,105(5):057202.
[3]Zhang Z Z,Liang J,Wang R Q,et al.Thermoelectricinduced spin currents in single-molecule magnet tunnel junctions[J].Applied Physics Letters,2010,97(24):242101.
[4]王瑞强,刘晨.量子点隧道结中自旋相关的电流关联[J].华南师范大学学报:自然科学,2011(4):71-74.Wang R Q,Liu C.Spin-dependent current correlation in quantum dot tunnel junction.[J].Journal of South China Normal University:Natural Science Edition,2011(4):71-74.
[5]Qi F H,Ying Y B,Jin G J.Temperature-manipulated spin transport through a quantum dot transistor[J].Physical Review B,2011,83(7):075310.
[6]Futterer D,Governale M,King J.Generation of pure spin currents by superconducting proximity effect in quantum dots[J].Europhysics Letters,2010,91(4):47004-47010.
[7]Futterer D,Governale M,Pala M G,et al.Nonlocal Andreev transport through an interacting quantum dot[J].Physical Review B,2009,79(5):054505.
[8]Ying Y B,Jin G J.Nonlocal tunnel magnetoresistance and thermal rectification effect in a nanoscale three-terminal junction[J].Journal of Physics:Condensed Matter,2012,24(49):495304.
[9]Wysoki ski K I.Thermoelectric transport in the three terminal quantum dot[J].Journal of Physics:Condensed Matter,2012,24(33):335303.
[10]Rozhkov A V,Arovas D P.Interacting-impurity Josephson junction:Variational wave functions and slave-boson mean-field theory[J].Physical Review B,2000,62(10):6687-6691.
[11]Karrasch C,Oguri A,Meden V.Josephson current through a single Anderson impurity coupled to BCS leads[J].Physical Review B,2008,77(2):024517.
[12]Meng T,Florens S.Self-consistent description of Andreev bound states in Josephson quantum dot devices[J].Physical Review B,2009,79(22):224521.
[13]Timm C.Tunneling through molecules and quantum dots:Master-equation approaches[J].Physical Review B,2008,77(19):195416.