Anomalous spin–orbit coupling in high-density two-dimensional electron gas confined in InGaAs/InAlAs quantum well

We study the magnetotransport property of a high-density two-dimensional electron gas confined in InGaAs/InAlAs quantum well. Both beating pattern in the Shubnikov–de Hass oscillation of resistivity and weak antilocalization effect are observed. From these two effects, Rashba spin-splitting energy is extracted. The extracted Rashba spin-splitting energy shows a nonmonotonic dependence on Fermi wave vector, contrary to the prevailing linear Rashba model. This anomalous behavior can be attributed to the nonlinear Rashba spin-splitting mechanism [Yang et al., Phys. Rev. B 74 (2006) 193314].

► Both beating pattern and weak antilocalization effect are observed in InGaAs/InAlAs quantum well. ► The extracted Rashba spin-splitting energy shows a nonmonotonic dependence on Fermi wave vector. ► This anomalous spin–orbit coupling can be attributed to the nonlinear Rashba spin-splitting mechanism.