Bismuth induced enhancement of Rashba spin–orbit interaction in GaAsBi/GaAs heterostructures

Abstract

The incorporation of heavy atoms into semiconductor heterostructures is a promising way to enhance the spin–orbit interaction of carriers moving in two-dimensional channels. We investigated the strength of spin–orbit interaction in a sample containing an epitaxially grown GaAsBi channel. Time- and spatially resolved Kerr rotation measurements revealed the existence of Rashba-type spin–orbit effective magnetic fields experienced by the photo-injected spins diffusing in the GaAsBi layer. The spin–orbit interaction parameters deduced from both experiments and theory suggest that, as a result of an increase in the spin–orbit split-off energy due to Bi, the offset energies of the valence band and spin split-off band at the GaAsBi/GaAs interface work constructively to enhance the Rashba spin–orbit interaction parameter, which is one order of magnitude larger than those arising from conventional GaAs/AlGaAs and InGaAs/GaAs interfaces.