Electron density effect on spin-orbit interaction in [001] GaAs quantum wells

TL;DR

This study demonstrates that the electron charge density in symmetric GaAs quantum wells significantly influences the Dresselhaus spin-orbit interaction, affecting spin-dependent phenomena in these systems.

Contribution

It reveals that 2D electron charge density can substantially modify the Dresselhaus spin-orbit interaction in symmetric quantum wells, a factor previously underappreciated.

Findings

Electron charge density renormalizes Dresselhaus interaction.

Internal electric fields from electrons affect spin-orbit coupling.

Implications for spin-dependent quantum well phenomena.

Abstract

The spin-orbit interaction of two-dimensional (2D) electrons in semiconductor quantum wells is usually considered to be determined by the band profile of a heterostructure. In the GaAs/AlGaAs type heterosystems, this interaction consists of the isotropic Bychkov-Rashba term, which is absent in symmetric wells, and the anisotropic Dresselhaus term, reflecting the lattice symmetry. It is well-known that the first term can be controlled by electric fields in the growth direction: external or internal, induced by a charge density of 2D electrons. In this work we reveal that the 2D electron charge can substantially affect also the Dresselhaus interaction in symmetric quantum wells. Within the one-band electron Hamiltonian containing, together with the bulk Dresselhaus interaction, the two contributions to the Dresselhaus term from the quantum well interfaces, we show that the internal electric field from the 2D electron charge density can substantially renormalize the anisotropic spin-orbit interaction of 2D electrons. This effect may be important in quantitative studies of spin-dependent phenomena in quantum wells.