Enhancement of Rashba Spin–Orbit Interaction Due to Wave Function Engineering

We have demonstrated an enhancement of Rashba spin–orbit interaction (SOI) in In0.53Ga0.47As/In0.7Ga0.3As/In0.53Ga0.47As double-step structure in comparison with In0.53Ga0.47As normal quantum well. In the double-step structure, high electron probability density is located on the In0.53Ga0.47As/In0.7Ga0.3As heterointerface to enhance the interface contribution of Rashba SOI. The double-step structure is designed based on k⋅p formalism considering field and interface contributions separately. The Rashba parameter α calculated by the k⋅p formalism shows good agreement with the experimental value by analyzing weak antilocalization. The large carrier density dependence of α is due to the In0.53Ga0.47As/In0.7Ga0.3As heterointerface contribution as well as the energy-band bending in the In0.7Ga0.3As quantum well. The results of this study suggest that the precise control of interface and field contributions in Rashba SOI will make its application to semiconductor spintronics.