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

Abstract

We report a study of suppressed spin dephasing for quasi-one-dimensional electron ensembles in wires etched into a GaAs/AlGaAs heterojunction system. Time-resolved Kerr-rotation measurements show a suppression that is most pronounced for wires along the [110] crystal direction. This is the fingerprint of a suppression that is enhanced due to a strong anisotropy in spin-orbit fields that can occur when the Rashba and Dresselhaus contributions are engineered to cancel each other. A surprising observation is that this mechanisms for suppressing spin dephasing is not only effective for electrons in the heterojunction quantum well, but also for electrons in a deeper bulk layer.

Colloquium: Persistent spin textures in semiconductor nanostructures

“…In the classic proposal of a spin field-effect transistor due to Datta and Das (1990) already sketched in Fig. 2, an electron is emitted from a spin-polarized electrode into a semiconductor region where its spin is rotated via electrically tunable Rashba coupling.…”

“…A paradigmatic example of a semiconductor spintronics device is the spin field-effect transistor (Datta and Das, 1990) schematically depicted in Fig. 2.…”

“…where the Rashba coefficient α is essentially proportional to the potential gradient across the quantum well and can therefore be varied experimentally. This contribution to spin-orbit interaction is the essential ingredience to the proposal for a spin field -effect transistor due to Datta and Das (1990) (Bychkov and Rashba, 1984;Rashba, 1960), it is nowadays discussed and studied in a much wider variety of structures lacking inversion symmetry; for a recent overview see Manchon et al (2015). A further source of spin-orbit coupling in two-dimensional structures are assymetric interfaces (Fabian et al, 2007); such contributions will not be considered in the following.…”

Weak localization in a lateral superlattice with Rashba and Dresselhaus spin-orbit interaction

“…9 Measurements of the spin-relaxation times in these systems have indicated that the strong spatial anisotropy is determining specific behavior, leading to the possibility of controlling such system parameters through the growth process of the LSL. 10 In this work we are inspired by the latter results to investigate the modulation effect induced by the Rashba (R) and Dresselhaus (D) SOI on the electric conductivity, as well as the anisotropy of the spin-relaxation rates within a unitary formalism derived in the weak localization approximation. Considering that the physical properties of the LSL are tuned in the growth process, our analysis bridges the theoretical discussion of isolated quantum wires 11,12 with that of the isotropic 2D systems.…”

A strong anisotropy of spin dephasing time of quasi-one dimensional electron gas in modulation-doped GaAs/AlGaAs wires

“…The coexistence of the Dresselhaus and Rashba SOIs leads to an anisotropic spin dynamics in 2DEG as a result of the orientation-dependent effective magnetic fields generated by the SOIs. [8][9][10] In particular, when the two types of SOI are nearly equal in magnitude, the resultant effective magnetic fields are aligned along the same direction, leading to a persistent spin helix (PSH) state. [11][12][13][14] In this state, the spin rotation depends only on the displacement, which is independent of the electron path.…”