Characterization of spin-orbit fields in InGaAs quantum wells

TL;DR

This study investigates spin dynamics in InGaAs quantum wells across temperatures, revealing a Rashba-type spin-orbit interaction with an estimated Rashba coefficient, and demonstrates the use of Kerr rotation to measure spin precession.

Contribution

It provides the first detailed measurement of spin-orbit fields and Rashba coefficients in 10-nm-wide InGaAs quantum wells using time-resolved Kerr rotation.

Findings

Spin lifetime exceeds 1 ns at 10 K and decreases with temperature.

Rashba symmetry of the spin-orbit interaction is confirmed.

Upper limit for Rashba coefficient is estimated at 2×10^{-12} eVm.

Abstract

Coherent electron spin dynamics in 10-nm-wide InGaAs/InAlAs quantum wells is studied from 10 K to room temperature using time-resolved Kerr rotation. The spin lifetime exceeds 1 ns at 10 K and decreases with temperature. By varying the spatial overlap between pump and probe pulses, a diffusive velocity is imprinted on the measured electron spins and a spin precession in the spin-orbit field is measured. A Rashba symmetry of the SOI is determined. By comparing the spatial precession frequency gradient with the spin decay rate, an upper limit for the Rashba coefficients $\alpha$ of 2$\times$10$^{-12}$ eVm is estimated.