Effective Dresselhaus and Rashba spin-orbit interactions in narrow quantum wells

TL;DR

This paper demonstrates that interfacial spin-orbit interactions significantly modify Rashba and Dresselhaus parameters in narrow quantum wells, explaining experimental variability and revealing interface-induced anisotropy even without electric fields.

Contribution

It introduces a method to calculate interfacial contributions to spin-orbit parameters, highlighting their importance in quantum well spin splitting.

Findings

Interfacial effects significantly renormalize Rashba and Dresselhaus parameters.

The model explains the variability in experimental data.

Interface asymmetry causes anisotropic spin splitting.

Abstract

Rashba and linear Dresselhaus interactions are believed to yield dominant contribution to the spin splitting of two-dimensional electrons in the quantum wells based on A$_3$B$_5$ compounds. We show that the interfacial spin-orbit interaction significantly renormalizes the value of the corresponding Rashba ($\alpha_{SIA}$) and Dresselhaus ($\alpha_{BIA}$) parameters. For this purpose, we solve the effective mass equation in a quantum well supplemented by the original boundary conditions on the atomically sharp interfaces and calculate the interfacial contributions to $\alpha_{SIA}$ and $\alpha_{BIA}$. Our results explain a considerable spread in the experimental data on spin-orbit parameters in GaAs/AlGaAs quantum wells. We also demonstrated that the non-equivalence of the interfaces leads to the anisotropy of the spin splitting even in quantum wells with zero average electric field.