We have investigated the spin-relaxation process of electrons at room temperature in undoped GaAs/AlGaAs multiple-quantum wells (MQWs) and InGaAs/InP MQWs. The spin-relaxation times are measured for different well thicknesses using time-resolved spin-dependent pump and probe absorption measurement. The spin-relaxation time, τs, for GaAs MQWs was found to depend on the electron confinement energy, E1e, according to τs ∝ E1e-2.2, demonstrating that the main spin-relaxation mechanism at room temperature is the D'yakonov-Perel' process. The measured spin-relaxation times of InGaAs MQWs whose band-gap is about half that of GaAs MQWs arc about 5 ps and vary depending on the quantum confinement energy, E1e, according to τs ∝ E1e-1.0. The spin-relaxation time by Elliott-Yafet process, which becomes stronger for narrower band-gap materials, is calculated for quantum wells and shown to vary according to τs ∝ E1e-1. The spin-relaxation mechanism and possible applications using this fast spin-relaxation process are discussed.
|Number of pages
|Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
|Published - 1999 Aug 15
ASJC Scopus subject areas
- General Engineering
- General Physics and Astronomy