Spin helices in GaAs quantum wells: Interplay of electron density, spin diffusion, and spin lifetime

Abstract

To establish a correlation between the spin diffusion, the spin lifetime, and the electron density, we study, employing time-resolved magneto-optical Kerr effect microscopy, the spin polarization evolution in low-dimensional GaAs semiconductors hosting two-dimensional electron gases. It is shown that for the establishment of the longest spin-lifetime, the variation of scattering rate with the electron density is of higher importance than the fulfilling of the persistent spin helix condition when the Rashba $\alpha$ and Dresselhaus $\beta$ parameters are balanced. More specifically, regardless of the $\alpha$ and $\beta$ linear dependencies on the electron density, the spin relaxation rate is determined by the spin diffusion coefficient that depends on electron density nonmonotonously. The longest experimental spin-lifetime occurs at an electron density, corresponding to the transition from Boltzmann to Fermi-Dirac statistics, which is several times higher than that when the persistent spin helix is expected. These facts highlight the role the electron density may play when considering applications for spintronic devices.

arXiv comment8 pages, 4 figures

References in corpus (19)

• 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
• Giant Spin Relaxation Anisotropy in Zinc-Blende Heterostructures
• Direct mapping of the formation of a persistent spin helix: Supplementary information
• Observation of spin Coulomb drag in a two-dimensional electron gas
• Gate-controlled spin-orbit interaction in a parabolic GaAs/AlGaAs quantum well
• Gate-tunable Spin-Galvanic Effect in Graphene Topological insulator van der Waals Heterostructures at Room Temperature
• Role of linear and cubic terms for the drift-induced Dresselhaus spin-orbit splitting in a two-dimensional electron gas
• Dynamics of a localized spin excitation close to the spin-helix regime
• Current-controlled Spin Precession of Quasi-Stationary Electrons in a Cubic Spin-Orbit Field
• Spatiotemporal spin fluctuations caused by spin-orbit-coupled Brownian motion
• Persistent Spin Helix Manipulation by Optical Doping of a CdTe Quantum Well
• Spin drift and diffusion in one- and two-subband helical systems
• Ultrafast supercontinuum fiber-laser based pump-probe scanning MOKE microscope for the investigation of electron spin dynamics in semiconductors at cryogenic temperatures with picosecond time and micrometer spatial resolution
• Gate-Control of Anisotropic Spin Transport and Spin Helix Dynamics in a Modulation-Doped GaAs Quantum Well
• Enhanced spin lifetimes in a two dimensional electron gas in a gate-controlled GaAs quantum well
• Non-equilibrium fractional quantum Hall states visualized by optically detected MRI
• Electromagnetic radiation detectors based on Josephson junctions: Effective Hamiltonian