Symmetry and spin dephasing in (110)-grown quantum wells

TL;DR

This paper investigates how symmetry affects spin dephasing in (110)-grown GaAs quantum wells, using photogalvanic effect and Kerr rotation to analyze symmetry control and spin relaxation times.

Contribution

It demonstrates that MPGE can probe quantum well symmetry and shows how to tune structure inversion asymmetry to optimize spin dephasing times.

Findings

Photocurrent only in asymmetric structures

Maximal spin relaxation time in symmetric QWs

Inversion asymmetry can be controlled via delta-doping

Abstract

Symmetry and spin dephasing of in (110)-grown GaAs quantum wells (QWs) are investigated applying magnetic field induced photogalvanic effect (MPGE) and time-resolved Kerr rotation. We show that MPGE provides a tool to probe the symmetry of (110)-grown quantum wells. The photocurrent is only observed for asymmetric structures but vanishes for symmetric QWs. Applying Kerr rotation we prove that in the latter case the spin relaxation time is maximal, therefore these structures set upper limit of spin dephasing in GaAs QWs. We also demonstrate that structure inversion asymmetry can be controllably tuned to zero by variation of delta-doping layer position.