共查询到20条相似文献,搜索用时 15 毫秒
1.
V. Ya. Demikhovskii A. V. Telezhnikov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2010,4(3):423-431
The electron energy spectrum and wave functions for a quasi-one-dimensional channel with Rashba spin-orbit coupling are calculated.
The dynamics of wave packets in thin wires based on GaAs/In0.23Ga0.77As and AlGaAs/GaAs heterostructures with Rashba spin-orbit coupling are studied. Spin polarizations are found. The effect
of splitting of wave packets with respect to their centers of mass and Zitterbewegung of their centers are discovered. The
characteristics of wave-packet oscillations and spin density for free electrons and under confinement conditions are compared.
A method for controlling the conductance of the quasi-one-dimensional channel using a controlling electrode is proposed. 相似文献
2.
P. Schwab R. Raimondi 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,25(4):483-495
We show that in the metallic phase of a two dimensional electron gas the spin-orbit coupling due to structure inversion asymmetry
leads to a characteristic anisotropy in the magnetoconductance. Within the assumption that the metallic phase can be described
by a Fermi liquid, we compute the conductivity in the presence of an in-plane magnetic field. Both the spin-orbit coupling
and the Zeeman coupling with the magnetic field give rise to two spin subbands, in terms of which most of the transport properties
can be discussed. The strongest conductivity anisotropy occurs for Zeeman energies of the order of the Fermi energy corresponding
to the depopulation of the upper spin subband. The energy scale associated with the spin-orbit coupling controls the strength
of the effect. More in particular, we find that the detailed behavior and the sign of the anisotropy depends on the underlying
scattering mechanism. Assuming small angle scattering to be the dominant scattering mechanism our results agree with recent
measurement on Si-MOSFET's in the vicinity of the metal-insulator transition.
Received 11 July 2001 相似文献
3.
We theoretically studied the spin-dependent charge transport in a two-dimensional electron gas with Dresselhaus spin-orbit coupling (DSOC) and metal junctions. It is shown that the DSOC energy can be directly measured from the tunneling conductance spectrum. We found that spin polarization of the conductance in the propagation direction can be obtained by injecting from the DSOC system. We also considered the effect of the interfacial scattering barrier (both spin-flip and non-spin-flip scattering) on the overall conductance and the spin polarization of the conductance. It is found that the increase of spin-flip scattering can enhance the conductance under certain conditions. Moreover, both types of scattering can increase the spin polarization below the branches crossing of the energy band. 相似文献
4.
《Current Applied Physics》2018,18(1):122-126
Based on the Green's function formalism, we investigated spin transport properties in one-dimensional three-terminal rings in the presence of the Rashba spin-orbit coupling (RSOC) and Dresselhaus spin-orbit coupling (DSOC). The conductance as a function of the Fermi energy shows typical resonance and antiresonance (conductance zero) characteristics in the absence of spin-orbit coupling (SOC). When one type of SOC (RSOC or DSOC) is introduced, the original conductance zeros are lifted, but new conductance zeros emerge. It is found that all the conductance zeros depend sensitively on the disorder, and the fluctuate weakens and smoothens the oscillations of the conductance. In the presence of both types of SOCs, the interplay between the RSOC and the DSOC opens a gap in the energy spectrum and breaks the cylindrical symmetry of the ring. Consequently, symmetrically coupled three-terminal rings show anisotropic conductances, which are robust against weak disorders. 相似文献
5.
The influence of the Dresselhaus spin-orbit coupling on spin polarization by tunneling through a disordered semiconductor superlattice was investigated. The Dresselhaus spin-orbit coupling causes the spin polarization of the electron due to transmission possibilities difference between spin up and spin down electrons. The electron tunneling through a zinc-blende semiconductor superlattice with InAs and GaAs layers and two variable distance InxGa(1−x)As impurity layers was studied. One hundred percent spin polarization was obtained by optimizing the distance between two impurity layers and impurity percent in disordered layers in the presence of Dresselhaus spin-orbit coupling. In addition, the electron transmission probability through the mentioned superlattice is too much near to one and an efficient spin filtering was recommended. 相似文献
6.
《Physics letters. A》2019,383(23):2813-2820
Spin dependent transport in one-dimensional four-terminal rings (FTRs) is investigated in the presence of the Rashba spin-orbit coupling (RSOC). In the absence of the RSOC, the conductances as a function of the electron wave vector show resonant behavior for symmetrical configurations. For asymmetrical configurations, the conductances show peculiar zero-conductance resonances, and two kinds of conductance zeros have been found. In the presence of the RSOC, the original conductance zeros disappear as new conductance zeros are generated. Moreover, two kinds of symmetry relations have been found in the conductances, the spin dependent conductances and the spin polarizations. For the FTRs with axial or central symmetry, the phase-locking effect has been found in terminal 2, where there is no spin polarization. Under a weak magnetic field, the Zeeman term is treated by a perturbation, and it is found that the Zeeman effect is obvious for weak RSOC. 相似文献
7.
D.M. Baltateanu 《Physics letters. A》2011,375(32):2952-2957
This Letter deals with the effect of a delta-potential barrier on the one-dimensional and asymmetric Aharonov-Bohm ring with Rashba spin-orbit interaction. The analytic expressions of the transmission amplitude and conductance are derived by applying the transfer matrix method in the one-electron scattering formalism. Resorting to an adequate tuning of the Aharonov-Bohm magnetic flux and Rashba coupling strength, a control of the conductance can be done by varying the strength and the location of the barrier. This may be useful in the design of further mesoscopic spin filters by using suitable asymmetry configurations. 相似文献
8.
Fano effect in a T-shaped double quantum dot structure in the presence of Rashba spin-orbit coupling
The influence of Rashba spin-orbit coupling on the Fano lineshape of the conductance spectrum in a T-shaped double quantum dot structure is theoretically studied. By second-quantizing the electron Hamiltonian in this structure, it is found that the Rashba interaction brings about a spin-flip interdot hopping term. With the enhancement of the Rashba interaction, this term separates the two resonant peaks in the conductance spectrum from each other. More importantly, it causes the broadening of the narrow Fano peak, and the narrowing of the broader peak. Finally, the asymmetric Fano lineshape changes into a symmetric profile in the global conductance spectrum. 相似文献
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12.
Tunable ground-state solitons in spin–orbit coupling Bose–Einstein condensates in the presence of optical lattices 下载免费PDF全文
Properties of the ground-state solitons, which exist in the spin–orbit coupling(SOC) Bose–Einstein condensates(BEC) in the presence of optical lattices, are presented. Results show that several system parameters, such as SOC strength,lattice depth, and lattice frequency, have important influences on properties of ground state solitons in SOC BEC. By controlling these parameters, structure and spin polarization of the ground-state solitons can be effectively tuned, so manipulation of atoms may be realized. 相似文献
13.
The spin glass transition of a quasi-1D organic-based magnet ([MnTPP][TCNE]) is explored using both ac and dc measurements. A scaling analysis of the ac susceptibility shows a spin glass transition near 4 K, with a viscous decay of the thermoremanent magnetization recorded above 4 K. We propose an extension to a fractal cluster model of spin glasses that determines the dimension of the spin clusters (D) ranging from approximately 0.8 to over 1.5 as the glass transition is approached. Long-range dipolar interactions are suggested as the origin of this low value for the apparent lower critical dimension. 相似文献
14.
We study effects of the oft-neglected cubic Dresselhaus spin-orbit coupling (i.e., directly proportional p3) in GaAs/AlGaAs quantum dots. Using a semiclassical billiard model, we estimate the magnitude of the spin-orbit induced avoided crossings in a closed quantum dot in a Zeeman field. Using previous analyses based on random matrix theory, we calculate corresponding effects on the conductance through an open quantum dot. Combining our results with an experiment on an 8 microm2 quantum dot [D. M. Zumbühl, Phys. Rev. B 72, 081305 (2005)10.1103/PhysRevB.72.081305] suggests that (1) the GaAs Dresselhaus coupling constant gamma is approximately 9 eV A3, significantly less than the commonly cited value of 27.5 eV A3, and (2) the majority of the spin-flip effects can come from the cubic Dresselhaus term. 相似文献
15.
We demonstrate that virtual excitations of higher radial modes in an atomic Bose gas in a tightly confining waveguide result in effective three-body collisions that violate integrability in this quasi-one-dimensional quantum system and give rise to thermalization. The estimated thermalization rates are consistent with recent experimental results in quasi-1D dynamics of ultracold atoms. 相似文献
16.
Priyadarshini Kapri Saurabh Basu 《The European Physical Journal B - Condensed Matter and Complex Systems》2017,90(2):33
The tunneling conductance for a junction device consisting of a normal metal and a singlet superconductor is studied with Rashba spin orbit coupling (RSOC) being present in the metallic lead and the interface separating the two regions via an extended Blonder-Tinkham-Klapwijk (BTK) formalism. Interesting interplay between the RSOC and a number of parameters that have experimental significance, and characterize either the junction or the superconducting leads, such as the barrier transparency, quasiparticle lifetime, Fermi wavevector mismatch, an in-plane magnetic field and their effects on the tunneling conductance are investigated in details for both a s-wave and a d-wave superconductor. In an opaque barrier, in presence of a quasiparticle lifetime, a Fermi wavevector mismatch or an external in-plane magnetic field, RSOC enhances the conductance corresponding to low biasing energies, that is, at energies lesser than the superconducting gap, while the reverse is noted for energies exceeding the magnitude of the gap. Further, there are exciting anomalies noted in the conductance spectrum for the d-wave gap which can be understood by incorporating the interplay between the superconducting gap and the angle of incident of the charge carriers. 相似文献
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18.
A semi-phenomenological theory of variable-range hopping (VRH) is developed for two-dimensional (2D) quasi-one-dimensional
(quasi-1D) systems such as arrays of quantum wires in the Wigner crystal regime. The theory follows the phenomenology of Efros,
Mott and Shklovskii allied with microscopic arguments. We first derive the Coulomb gap in the single-particle density of states,
g(ε), where ε is the energy of the charge excitation. We then derive the main exponential dependence of the electron conductivity
in the linear (L), i.e. σ(T) ∼exp [-(TL/T)γL], and current in the non-linear (NL), i.e.
, response regimes (
is the applied electric field). Due to the strong anisotropy of the system and its peculiar dielectric properties we show
that unusual, with respect to known results, Coulomb gaps open followed by unusual VRH laws, i.e. with respect to the disorder-dependence
of TL and
and the values of γL and γNL. 相似文献
19.
We present a systematic theoretical study of the BCS-BEC crossover in two-dimensional Fermi gases with Rashba spin-orbit coupling (SOC). By solving the exact two-body problem in the presence of an attractive short-range interaction we show that the SOC enhances the formation of the bound state: the binding energy E(B) and effective mass m(B) of the bound state grows along with the increase of the SOC. For the many-body problem, even at weak attraction, a dilute Fermi gas can evolve from a BCS superfluid state to a Bose condensation of molecules when the SOC becomes comparable to the Fermi momentum. The ground-state properties and the Berezinskii-Kosterlitz-Thouless (BKT) transition temperature are studied, and analytical results are obtained in various limits. For large SOC, the BKT transition temperature recovers that for a Bose gas with an effective mass m(B). We find that the condensate and superfluid densities have distinct behaviors in the presence of SOC: the condensate density is generally enhanced by the SOC due to the increase of the molecule binding; the superfluid density is suppressed because of the nontrivial molecule effective mass m(B). 相似文献
20.
G.N. Katomeris S.N. Evangelou 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,16(1):133-136
We examine the validity of the recently proposed semi-Poisson level spacing distribution function P(S), which characterizes “critical quantum chaos”, in 2D disordered systems with spin-orbit coupling. At the Anderson transition
we show that the semi-Poisson P(S) can describe closely the critical distribution obtained with averaged boundary conditions, over Dirichlet in one direction
with periodic in the other and Dirichlet in both directions. We also obtain a sub-Poisson linear number variance , with asymptotic value . The obtained critical statistics, intermediate between Wigner and Poisson, is discussed for disordered systems and chaotic
models.
Received 1 September 1999 相似文献