Controllable Spin-Polarized Transport in a Three-Terminal Model

《Controllable Spin-Polarized Transport in a Three-Terminal Model》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、Commun.Theor.Phys.57(2012)1081–1086Vol.57,No.6,June15,2012ControllableSpin-PolarizedTransportinaThree-TerminalModel∗LIANGFeng(1,†22ù¸),YANGYong-Hong([÷),andWANGJun(
)1DepartmentofPhysics,HuaiyinInstituteofTechnology,Huaian223003,China2DepartmentofPhysics,SoutheastUniversity,Nanj

2、ing211189,China(ReceivedNovember18,2011;revisedmanuscriptreceivedFebruary23,2012)AbstractBymeansoftheKeldyshGreen’sfunctionmethod,weinvestigatethespin-polarizedelectrontransportinathree-terminaldevice,whichiscomposedofthreenormalmetalleadsandtwoserially-coupledquantumdots(QDs).Th

3、eRashbaspin-orbitinteraction(RSOI)isalsoconsideredinoneoftheQDs.Weshowthatthespin-polarizedchargecurrentwitharbitraryspinpolarizationcanbeobtainedbecauseofthequantumspininterferenceeffectarisingfromtheRashbaspinprecessionphase,anditcanbemodulatedbythesystemparameterssuchastheappli

4、edexternalvoltages,theRSOIstrength,theQDlevels,aswellasthedot-leadcouplingstrengths.Moreover,afullyspin-polarizedcurrentorapurespincurrentwithoutanyaccompanyingchargecurrentcanalsobecontrolledtoflowinthesystem.Ourfindingsindicatethattheproposedmodelcanserveasanall-electricalspindev

5、iceinspintronicsfield.PACSnumbers:72.25.Dc,73.23.-b,73.63.-bKeywords:spintronics,spincurrent,Rashbaspin-orbitinteraction,quantumdot,KeldyshGreen’sfunction1IntroductionRecently,someall-electricalschemeshaveemergedinliteratures[24−31]andmostofthemarebasedontheRSOI,Inrecentyears,much

6、efforthasbeendevotedtocon-trollingandengineeringelectronspininthemesoscopicsincetheRSOIcouplesthespindegreeoffreedomofelec-structures,whichhasledtoanewsubfieldofcondensedtrontoitsorbitmotionandthestrengthoftheRSOIcanmatterphysicsusuallyreferredtoasspintronics.[1−4]Onebeconveniently

7、controlledbyanexternalelectricfieldoragatevoltage.[25−26]Forexample,thepossibilityofrealiz-ofthekeyissuesinthisemergingfieldishowtoefficientlygenerateandcontrolaspin-polarizedcurrentthroughainganall-electricalspinpumpinginsemiconductornanos-tructureswithSOIhasbeenstudied.[27−32]There

8、sultsmesoscopicsystem.Uptonow,variousexp