Modeling of diffusion of injected electron spins in spin-orbit coupled microchannels

Abstract

We report on a theoretical study of spin dynamics of an ensemble of spin-polarized electrons injected in a diffusive microchannel with linear Rashba and Dresselhaus spin-orbit coupling. We explore the dependence of the spin-precession and spin-diffusion lengths on the strengths of spin-orbit interaction and external magnetic fields, microchannel width, and orientation. Our results are based on numerical Monte Carlo simulations and on approximate analytical formulas, both treating the spin dynamics quantum-mechanically. We conclude that spin-diffusion lengths comparable or larger than the precession-length occur i) in the vicinity of the persistent spin helix regime for arbitrary channel width, and ii) in channels of similar or smaller width than the precession length, independent of the ratio of Rashba and Dresselhaus fields. For similar strengths of the Rashba and Dresselhaus fields, the steady-state spin-density oscillates or remains constant along the channel for channels parallel to the in-plane diagonal crystal directions. An oscillatory spin-polarization pattern tilted by 45${}^{\circ }$ with respect to the channel axis is predicted for channels along the main cubic crystal directions. For typical experimental system parameters, magnetic fields of the order of Tesla are required to affect the spin-diffusion and spin-precession lengths.

Replaced with final version (some explanations and figures improved). 8 pages, 6 figures

References in corpus (18)

• Spintronics: Fundamentals and applications
• Non-ballistic spin field-effect transistor
• An Exact SU(2) Symmetry and Persistent Spin Helix in a Spin-Orbit Coupled System
• Emergence of the persistent spin helix in semiconductor quantum wells
• Spin dynamics in semiconductors
• Semiclassical theories of the anomalous Hall effect
• Non-magnetic semiconductor spin transistor
• Dimensional Control of Antilocalisation and Spin Relaxation in Quantum Wires
• Non-diffusive spin dynamics in a two-dimensional electron gas
• Spin relaxation in a generic two-dimensional spin-orbit coupled system
• Diffusive and precessional spin dynamics in a two-dimensional electron gas with disorder: a gauge theory view
• Spin-injection Hall effect in a planar photovoltaic cell
• Semiclassical Monte Carlo Model for In-Plane Transport of Spin-Polarized Electrons in III-V Heterostructures
• Tuning of structure inversion asymmetry by the $\delta$-doping position in (001)-grown GaAs quantum wells
• Anisotropic spin transport in GaAs quantum wells in the presence of competing Dresselhaus and Rashba spin-orbit-coupling strengths
• Datta-Das type spin-field effect transistor in non-ballistic regime
• Spin relaxation under identical Dresselhaus and Rashba coupling strengths in GaAs quantum wells
• Physical Limits of the ballistic and non-ballistic Spin-Field-Effect Transistor: Spin Dynamics in Remote Doped Structures

Cited by in corpus (4)

• Spin Hall effect transistor
• Suppressed decay of a laterally confined persistent spin helix
• Controlled rotation of electrically injected spins in a non-ballistic spin field-effect transistor
• Spin diffusion in $n$-type (111) GaAs quantum wells