21 research outputs found
Thermoelectric response of spin polarization in Rashba spintronic systems
Motivated by recent discovery of strongly spin-orbit coupled two-dimensional
(2D) electron gas near the surface of Rashba semiconductors BiTeX (X=Cl, Br,
I), we calculate thermoelectric responses of spin polarization in 2D Rashba
model using an exact solution of the linearized Boltzmann equation for elastic
scattering. When the Fermi energy lies below the band crossing point we
find a non-Edelstein electric-field induced spin polarization which is linear
in . We show that the Mott-like relation between spin polarizations
induced by the temperature gradient and electric field breaks down
significantly when lies in the vicinity of the band crossing point. As
the temperature tends to zero, the temperature-gradient induced spin
polarization vanishes. These results differ from previous ones obtained by
relaxation time approximations.Comment: 9 pages, 3 figure
Unconventional thermoelectric behaviors and enhancement of figure of merit in Rashba spintronic systems
Thermoelectric transport in strongly spin-orbit coupled two-dimensional
Rashba system is studied using the exact solution of the linearized Boltzmann
equation. Some unusual transport behaviors are revealed. We show that the
electrical conductivity takes a Drude form when the Fermi energy is
above the band crossing point, but a non-Drude form which is a quadratic
function of when lies below the band crossing point. The Mott
relation breaks down when lies in the vicinity of the band crossing
point. It is shown that the thermopower and thermoelectric figure of merit are
strongly enhanced when downs below the band crossing point. This
enhancement is attributed to not only the one-dimensional-like density of state
but also the unconventional intraband elastic scattering below the band
crossing point. The differences between these results and those obtained by the
relaxation time approximation are discussed in detail.Comment: 9 pages, 5 figure
Controllable quantum spin precession by Aharonov-Casher phase in conducting ring
We investigate quantum spin transport in a structure of conducting ring,
embedded in textured electric field, with two leads, and obtain an exact
solution for the problem. The spin precession induced by the Aharonov-Casher
phase is studied. It is shown that the spin-polarized current and its
polarizability can be controlled by the electric field. As a result the
polarizability is a function of the geometric phase which originates from the
spin-orbital interaction in the ring.
72.25.-b, 03.65.VfComment: 10 pages, 4 figure
Photon-assisted Fano Resonance and Corresponding Shot-Noise in a Quantum Dot
We have studied the Fano resonance in photon-assisted transport in a quantum
dot and calculated both the coherent current and spectral density of shot
noise. It is predicted, for the first time, that the shape of Fano profile will
also appear in satellite peaks. It is found that the variations of Fano
profiles with the strengths of nonresonant transmissions are not synchronous in
absorption and emission sidebands. The effect of interference on
photon-assisted pumped current has been also investigated. We further predict
the current and spectral density of shot noise as a function of the phase,
which exhibits an intrinsic property of resonant and nonresonant channels in
the structures.Comment: 4 pages, 5 figure
Enhancement of polarization in a spin-orbit coupling quantum wire with a constriction
We investigate the enhancement of spin polarization in a quantum wire in the
presence of a constriction and a spin-orbit coupling segment. It is shown that
the spin-filtering effect is significantly heightened in comparison with the
configuration without the constriction. It is understood in the studies that
the constriction structure plays a critical role in enhancing the spin
filtering by means of confining the incident electrons to occupy one channel
only while the outgoing electrons occupy two channels. The enhancement of
spin-filtering has also been analyzed within the perturbation theory. Because
the spin polarization arises mainly from the scattering between the
constriction and the segment with spin-orbit coupling, the sub-band mixing
induced by spin-orbit interaction in the scattering process and the
interferences result in higher spin-filtering effect.Comment: 8 pages, 7 figure
Spin-orbit interaction enhanced polaron effect in two-dimensional semiconductors
It is shown that in two-dimensional semiconductors, the electron-phonon interaction and polaronmass correction are both significantly enhanced by the Rashba spin-orbit coupling. The masscorrection is positive for the upper Rashba branch and negative for the lower Rashba branch. BothRashba branches have the same polaron binding energy, which is higher than that for systems in theabsence of spin-orbit interaction. To the leading order, the correction to the binding energy isproportional to the square of the spin-orbit coupling strength
(2-Aminophenyl)methyldiphenylphosphonium iodide
The asymmetric unit of the title compound, C19H19NP+·I−, contains two tetraalkylphosphonium cations and two I− anions. The P atoms are four-coordinated in distorted tetrahedral configurations by three phenyl and one methyl C atoms. There are weak intra- and intermolecular N—H...I contacts