Anomalous spin-orbit effects in a strained InGaAs/InP quantum well structure

Abstract

There is currently a large effort to explore spin-orbit effects in semiconductor structures with the ultimate goal of manipulating electron spins with gates. A search for materials with large spin-orbit coupling is therefore important. We report results of a study of spin-orbit effects in a strained InGaAs/InP quantum well. The spin-orbit relaxation time, determined from the weak antilocalization effect, was found to depend nonmonotonically on gate voltage. The spin-orbit scattering rate had a maximum value of 5 71010 s 121 at an electron density of n=3 71015 m 122. The scattering rate decreased from this for both increasing and decreasing densities. The smallest measured value was approximately 109 s 121 at an electron concentration of n=6 71015 m 122. This behavior could not be explained by either the Rashba or the bulk Dresselhaus mechanisms but is attributed to asymmetry or strain effects at dissimilar quantum well interfaces.NRC publication: Ye