Spin-Dephasing Anisotropy for Electrons in a Diffusive Quasi-1D GaAs Wire

Abstract

We present a numerical study of dephasing of electron spin ensembles in a diffusive quasi-one-dimensional GaAs wire due to the D'yakonov-Perel' spin-dephasing mechanism. For widths of the wire below the spin precession length and for equal strength of Rashba and linear Dresselhaus spin-orbit fields a strong suppression of spin-dephasing is found. This suppression of spin-dephasing shows a strong dependence on the wire orientation with respect to the crystal lattice. The relevance for realistic cases is evaluated by studying how this effect degrades for deviating strength of Rashba and linear Dresselhaus fields, and with the inclusion of the cubic Dresselhaus term.

Suppressed spin dephasing for two-dimensional and bulk electrons in GaAs wires due to engineered cancellation of spin-orbit interaction terms

“…The dependence of 2DEG dephasing on wire orientation is here less strong than expected for exact cancellation for C D1 = C R . 4,15 Instead, it is consistent with simulations for ͉C D1 + C R ͉ / ͉C D1 − C R ͉Ϸ3 and C D1 and C R as reported values. 3 We cannot make more detailed statements about C D1 and C R values since we analyzed that this should account for the influence of the cubic Dresselhaus SOI, momentum relaxation, and electron-hole recombination on the observed Kerr signals.…”

“…19 To investigate the above scenario, we use a simple model and Monte Carlo simulations as for 2DEG-based wires. 15 We model a wire of bulk material by assuming a randomly moving electron ensemble with a three-dimensional k-vector distribution that is confined to a rectangular elongated box with short sides of 1 m. The electrons are scattering on the edge of the box and on impurities ͑mean free path from impurities alone set at 1 m, i.e., a quasiballistic electron ensemble͒. The ͑quasi-͒Fermi level is derived from the estimated photoelectron density around the superlattice ͑ϳ3 ϫ 10 21 m −3 ͒.…”

“…Further studies with tuning of SOI by a gate gives access to better cancellation of Rashba and Dresselhaus SOI, and can explore the ultimate limit of suppressing dephasing in wires. 4,15 Such gate control can also yield spin-transistor functionality 1 by associating on and off with strong or little dephasing of spin signals. Our results also establish that using SDA for suppressing dephasing is not restricted to quantum-well electron ensembles.…”

Direction Dependence of Spin Relaxation in Confined Two-Dimensional Systems

“…This has also been studied numerically in quasi-1D GaAs wires. 3 In this proceedings we present analytical results concerning this anisotropy for the 2D case as well as the case of QW with spin and charge conserving boundaries. Hereby we focus on materials where the dominant mechanism for spin relaxation is governed by the D'yakonovPerel spin relaxation.…”

Dynamics of spin relaxation in finite-size two-dimensional systems: An exact solution

“…The main result of our work is given by Eqs. (22) and (23) describing the time and space dependence of spin polarization components. Section III presents numerical Monte Carlo simulations of spin dynamics that are in an excellent agreement with our analytical results.…”