Mobility dependence of electron spin relaxation time in n-type InGaAs/InAlAs multiple quantum wells

We have measured electron spin relaxation time (τe) in undoped and n-type InGaAs/InAlAs quantum wells (QWs) as a function of electron quantized energy (E1e) and electron mobility (μ) at room temperature. For E1e dependence, the trend can be explained either by the Dʹyakonov–Perel’ (DP) theory or by the Elliott–Yafet (EY) theory. On the other hand, it is difficult to explain the complex μ-dependence of τe by either of the theories. Our experimental results suggest that further improvement of the theories might be necessary to fully explain the relaxation mechanism in InGaAs QWs.