Anisotropic spin transport in GaAs quantum wells in the presence of competing Dresselhaus and Rashba spin-orbit-coupling strengths

Abstract

Aiming at the optimization of the spin diffusion length in (001) GaAs quantum wells, we explore the effect of the anisotropy of the spin-orbit coupling on the competition between the Rashba and the Dresselhaus spin-orbit couplings by solving the kinetic spin Bloch equations with the electron-phonon and the electron-electron scattering explicitly included. For identical strengths of the Rashba and the Dresselhaus spin-orbit couplings, the spin diffusion length shows strong anisotropy not only for the spin polarization direction but also for the spin diffusion direction. Two special directions are used seeking for the large diffusion length: ($\bar{1}$10) and (110). Without the cubic term of the Dresselhaus spin-orbit coupling and with the identical Dresselhaus and Rashba strengths, infinite diffusion lengths can be obtained {\em either} for the spin diffusion/injection direction along $(\bar{1}10)$, regardless of the direction of spin polarization, {\em or} for the spin polarization along $(110)$, regardless of the direction of the spin diffusion/injection. However, the cubic Dresselhaus term cannot be neglected, resulting into a finite spin diffusion length which decreases with the temperature and the electron density, and of which the anisotropy for the spin diffusion direction and spin polarization direction is maintained. For the spin diffusion/injection direction along ($\bar{1}$10), the spin diffusion length increases first with the increase of the Rashba strength (from 0) which can be tuned by the external gate voltage; when the Rashba strength is slightly smaller than (in stead of equal to) the Dresselhaus strength, the diffusion length reaches its maximum; and then it decreases with the Rashba strength.

8 pages, 5 figures, to be published in PRB.

References in corpus (8)

• High temperature spin dephasing in n-typed GaAs quantum wells
• Hot-electron effect in spin dephasing in $n$-type GaAs quantum wells
• Spin susceptibilities, spin densities and their connection to spin-currents
• Suppression of the D'yakonov-Perel' spin relaxation mechanism for all spin components in [111] zincblende quantum wells
• Kinetic theory of spin transport in n-typed semiconductor quantum wells
• Spin relaxation under identical Dresselhaus and Rashba coupling strengths in GaAs quantum wells
• Modulation of spin dynamics in a channel of a non-ballistic spin field effect transistor
• Spin oscillations in transient diffusion of a spin pulse in n-type semiconductor quantum wells

Cited by in corpus (3)

• Detection of large magneto-anisotropy of electron spin dephasing in a high-mobility two-dimensional electron system in a $[001]$ GaAs/AlGaAs quantum well
• Spin relaxation in $n$-type GaAs quantum wells with transient spin grating
• Non-Markovian hole spin kinetics in $p$-type GaAs quantum wells