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Aharonov-Casher oscillasions of transmission through a mesoscopic ring with a magnetic impurity is investigated.Both spin-dependent transmission and reflection coefficients of spin-state electrons at zero-temperature are calculated as a function of the textured electric fields and its title angle in the present of spin-flipper scattering.It is found that the spin-exchange interaction can destroy intermittently periodic oscillations of spin-up transmission and reflection coefficients within some small ranges in the adiabatic region of quantum phase.However spin-down transmission and reflection coefficients appear periodic AC oscillations.The calculated results manifest that spindown transmission and reflection coefficients have the same perfect oscillation patterns.In the nonadiabatic region, the behavior of the anomalous AC oscillations are depedent on the difference between the tilt angle of spin and that of texture electric field. 相似文献
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1 Introduction Quantumtransportinmesoscopicsystemshasbeenextensivelyinvestigatedinthe pasttwodecades[1] .SinceWeesetal[2 ] .andWharametal[3] .discoveredthe phenomenonofconductance quantizationofanelectronthroughanarrow pointcontactstructure ,therehavebeenanumberofotherworkswhichcon centratedonstudyingelectronscatteringfromimpuri tiesinanarrowquantumconductorwire .BagwellandAvishaietal[4 9] .haveexaminedtheinfluencesofscatteringfromimpuritiesontheelectrontransmis sioninquantumwirebyusingthe… 相似文献
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Spin-polarized transport through a precessing magnetic spin coupled to ferromagnetic electrodes is studied using a non-equilibrium Green＇s function approach. The characteristic of conductance is obtained at zero temperature. We find that competition between spin-exchange interaction on the spin site and spin-orbit interaction in the barriers dominates the resonant behavior of conductance. In a parallel configuration, conductance peaks have identical amplitude. With the angle θ increasing, the width of resonant peaks is broadened or narrowed for different spin coherent states. In an anti-parallel case, spin-flip tunneling in the barriers will essentially enhance amplitude of the conductance peak. 相似文献
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1 Ｉｎｔｒｏｄｕｃｔｉｏｎ ＵｌｔｒａｆｉｎｅｐａｒｔｉｃｌｅｓｏｆｍａｇｎｅｔｉｃｍａｔｅｒｉａｌｓｓｕｃｈａｓＦｅ,Ｃｏ,Ｎｉａｎｄｔｈｅｉｒａｌｌｏｙｓｈａｖｅｔｈｅｐｏｔｅｎｔｉａｌａｐｐｌｉｃａｔｉｏｎｓｉｎｍａｇｎｅｔｉｃｒｅｃｏｒｄｉｎｇ,ｆｅｒｒｏｆｌｕｉｄｓ,ｍｅｄｉｃａｌｄｉａｇｎｏｓｔｉｃｅｔｃ..Ｔｈｅｍａｇｎｅｔｉｃｐｒｏｐｅｒｔｉｅｓｏｆｆｉｎｅｐａｒｔｉｃｌｅｓｄｉｆｆｅｒｍａｇｎｉｆｉｃｅｎｔｌｙｆｒｏｍｔｈｏｓｅｏｆｌａｒｇｅｐａｒｔｉｃｌｅｓ,ａｎｄｔｈｅｒｅｌａｔ… 相似文献
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1IntroductionQuantumtransport in mesoscopic systems has beenextensively investigated in the past two decade[1].Since Wees ,et al.[2]and Wharam,et al.[3]discov-ered the phenomenon of conductance quantization ofan electron through a narrow two-di mensional con-striction,there have been a number of other works ,which are concentrated on studying electron scatteringfrom i mpurities in a narrow quantum conductorwire[4-10].Bagwell and Avishai ,et al.[4-6]have exam-ined the influences of scattering … 相似文献
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Oscillations of the spin-polarized conductance controlled by a uniform magnetic field in a modified Aharonov-Bohm ring is studied with use of one-dimensional quantum wave guide.Its expression at zero temperature is obtained as a function of the flux penetrating the ring and the magnetic field.It has been found that there are two kinds of polarized conductance extremas for a given Fermienergy.As Zeemann energy of spin-polarized electron in the stub is varied.one kind of extrema exhibits continuous phase shift .However,another is locked at particular values of phase shift and it can only change abrouptly from a maxima to a minima when Zeemann crosses the level of the bound state of isolated stub.This is a different mehanism for abrupt change phase of conductance osillations. 相似文献
7.
Aharonov-Casher oscillasions of transmission through a mesoscopic ring with a magnetic impurity is investigated. Both spindependent transmission and reflection coefficients of spin-state electrons at zero-temperature are calculated as a function of the textured electric fields and its title angle in the present of spin-flipper scattering. It is found that the spin-exchange interaction can destroy intermittently periodic oscillations of spin-up transmission and reflection coefficients within some small ranges in the adiabatic region of quantum phase. However spin-down transmission and reflection coefficients appear periodic AC oscillations. The calculated results manifest that spindown transmission and reflection coefficients have the same perfect oscillation patterns. In the nonadiabatic region, the behavior of the anomalous AC oscillations are depedent on the difference between the tilt angle of spin and that of texture electric field. 相似文献
8.
The paper studies photon-associated transmission through a quantum wire with a side-coupled stub tuner,to which an external microwave field applies,in terms of the approach developed by Cai.The inelastic scattering of an incoming electron and thd photon field lead to photon-electronic transmission though quantum wier.It is found that single photon absorbing (emitting) of the incoming electron in the stub can bring about antiresonant transmission in the quantum wire.The influence of the feedback mechanism from inelastic scattering process on elastic channel transmission is also examined.Total transmission coefficient as a function of photon energy exhibits non-periodic oscillation peaks.With the increasing of photon-electron coupling constant,the amplitude of these oscillation peaks enhances. 相似文献
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1 Introduction Since some experi ments made by Yacoby,et al.[1],and Schuster ,et al.[2],that first measured electrontransmission phase through a quantum dot ( QD) ,phase sensitive transports in open mesoscopic ringwith a QD have been extensively investiga… 相似文献
10.
We investigate alternating response of the spin current in a quantum dot system coupled to a normal metal electrode,to which an alternating driving voltage and a pumping rotating magnetic field are applied.The expression of the time-averaged spin current and its differential is obtained based on a non-equilibrium Green's function method.We find that for a given rotating frequency,the spin current increases rapidly and appears to have small steps when the driven frequency increases.As the driven frequency is further increasing,the spin current can be significantly enhanced and approaches a stable value.The photon-assisted processes bring about interesting features of spin current.The influence of the gate voltage and temperature on the spin current is examined in detail. 相似文献
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