Spin relaxation in the presence of crossed electric and magnetic fields: A quasiclassical approach

The spin and density response functions in the random phase approximation (RPA) are derived by linearizing the kinetic equation including a magnetic field, the spin-orbit coupling, and mean fields with respect to an external electric field. Different polarization functions appear describing various precession motions showing Rabi satellites due to an effective Zeeman field. The latter turns out to consist of the mean-field magnetization, the magnetic field, and the spin-orbit vector. The collective modes for charged and neutral systems are derived and a threefold splitting of the spin waves dependent on the polarization and spin-orbit coupling is shown. The dielectric function including spin-orbit coupling, polarization and magnetic fields is presented analytically for long wave lengths and in the static limit. The dynamical screening length as well as the long-wavelength dielectric function shows an instability in charge modes, which are interpreted as spin segregation and domain formation. The spin response describes a crossover from damped oscillatory behavior to exponentially damped behavior dependent on the polarization and collision frequency. The magnetic field causes ellipsoidal trajectories of the spin response to an external electric field and the spin-orbit coupling causes a rotation of the spin axes. The spin-dephasing times are extracted and discussed in dependence on the polarization, magnetic field, spin-orbit coupling and single-particle relaxation times.

“…(45) corresponds to the precession term found in Ref. 31 as an additional rotation of the magnetization.…”

Section: Long-wavelength Limitmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Kinetic theory of spin-polarized systems in electric and magnetic fields with spin-orbit coupling. II. RPA response functions and collective modes

Morawetz

2015

“…Such rotations of the magnetic moment were studied previously both for hopping of small polarons 24,26 and for extended states in a two-dimensional electron gas. 27,28 In analogy to space-charge waves, these eigenmodes are called spin-remagnetization waves. Typically, the amplitude of these excitations exponentially decrease with increasing time.…”

Section: Field-induced Spin Accumulation and Hanle Effectmentioning

confidence: 99%

Spin polarization in biased Rashba-Dresselhaus two-dimensional electron systems

Kleinert

Bryksin²

2007

Based on spin-charge coupled drift-diffusion equations, which are derived from kinetic equations for the spin-density matrix in a rigorous manner, the electric-field-induced nonequilibrium spin polarization is treated for a two-dimensional electron gas with both Rashba and Dresselhaus spinorbit coupling. Most emphasis is put on the consideration of the field-mediated spin dynamics for a model with equal Rashba and Dresselhaus coupling constants, in which the spin relaxation is strongly suppressed. Weakly damped electric-field-induced spin excitations are identified, which remind of space-charge waves in crystals.

“…5 As the electronelectron Coulomb scattering does not contribute to the momentum relaxation time τ p , it has long been widely believed that the electron-electron Coulomb scattering is irrelevant in the spin relaxation. 5,6,7,8,9,10,11 However, it was first pointed out by Wu and Ning 12 that in the presence of inhomogeneous broadening, any scattering, including the spin conserving electron-electron Coulomb scattering, can cause an irreversible spin relaxation and dephasing. This inhomogeneous broadening can be the energy-dependent g-factor, 12 the DP term, 13,14 and even the k-dependent spin diffusion along a spacial gradient.…”

mentioning

confidence: 99%

Effect of electron-electron scattering on spin dephasing in a high-mobility low-density two-dimensional electron gas

Ruan

Luo

et al. 2008

Utilizing time-resolved Kerr rotation techniques, we have investigated the spin dynamics of a high mobility, low density two dimensional electron gas in a GaAs/Al 0.35 Ga 0.65 As heterostructure in dependence on temperature from 1.5 K to 30 K. It is found that the spin relaxation/dephasing time under a magnetic field of 0.5 T exhibits a maximum of 3.12 ns around 14 K, superimposed on an increasing background with rising temperature. The appearance of the maximum is ascribed to that at the temperature where the crossover from the degenerate to the nondegenerate regime takes place, electron-electron Coulomb scattering becomes strongest, and thus inhomogeneous precession broadening due to D'yakonov-Perel' (DP) mechanism becomes weakest. These results agree with the recent theoretical predictions [Zhou et al., PRB 75, 045305 (2007)], verifying the importance of electron-electron Coulomb scattering to electron spin relaxation/dephasing. PACS numbers: 72.25.Rb, 71.70.Ej, 78.47.jc In recent years, spin dynamics in semiconductors has attracted considerable attention because of its potential application in the spin-based devices. 1 The operation of these devices requires spin lifetime long enough to achieve storage, transport and processing of information. Therefore, a comprehensive understanding of spin relaxation mechanism is a key factor for the realization of these devices. It is generally accepted that the D'yakonov-Perel' (DP) mechanism is the leading spin relaxation/dephasing (R/D) mechanism in n-type zincblende semiconductors. 2 This is caused by an wavevector kdependent effective magnetic field Ω(k) from the bulk inversion asymmetry, 3 i.e., the Dresselhaus term, and/or the structure inversion asymmetry, 4 i.e., the Rashba term. The spin relaxation rate can be determined by τ −1 = Ω(k) 2 τ P (k), where τ P (k) is the momentum relaxation time. 5 As the electronelectron Coulomb scattering does not contribute to the momentum relaxation time τ p , it has long been widely believed that the electron-electron Coulomb scattering is irrelevant in the spin relaxation. 5,6,7,8,9,10,11 However, it was first pointed out by Wu and Ning 12 that in the presence of inhomogeneous broadening, any scattering, including the spin conserving electron-electron Coulomb scattering, can cause an irreversible spin relaxation and dephasing. This inhomogeneous broadening can be the energy-dependent g-factor, 12 the DP term, 13,14 and even the k-dependent spin diffusion along a spacial gradient. 15 In n-type GaAs quantum well, the importance of the electron-electron scattering to the spin relaxation was proved by Glazov and Ivchenko 16 by using perturbation theory and Weng and Wu 14 from a fully microscopic many-body approach. In a temperature-dependent experimental study of the spin relaxation in n-type (001) quantum wells, Harleyet al. indirectly verified the effects of the electron-electron scattering on spin relaxation. 17,18 Nevertheless, the importance of the Coulomb scattering to the spin relaxation/dephasing (R/D)has not yet been ...