Spin relaxation under identical Dresselhaus and Rashba coupling strengths in GaAs quantum wells

TL;DR

This study investigates spin relaxation in GaAs quantum wells with equal Dresselhaus and Rashba couplings, comparing different statistical models and analyzing the effects of cubic Dresselhaus terms on relaxation times.

Contribution

It demonstrates the marginal difference between traditional and helix statistics and reveals the finite spin relaxation time along a specific direction when including cubic Dresselhaus terms.

Findings

Minimal difference between the two statistical models.

Finite spin relaxation time along (1,1,0) with cubic Dresselhaus term.

Longer relaxation time along the (1,1,0) direction compared to others.

Abstract

Spin relaxation under identical Dresselhaus and Rashba coupling strengths in GaAs quantum wells is studied in both the traditional collinear statistics, where the energy spectra do not contain the spin-orbit coupling terms, and the helix statistics, where the spin-orbit couplings are included in the energy spectra. We show that there is only marginal difference between the spin relaxation times obtained from these two different statistics. We further show that with the cubic term of the Dresselhaus spin-orbit coupling included, the spin relaxation time along the (1,1,0) direction becomes finite, although it is still much longer than that along the other two perpendicular directions. The properties of the spin relaxation along this special direction under varies conditions are studied in detail.