Manipulation of the rashba spin-orbit interaction in double-sided doped In_0.53Ga_0.47As/InAs quantum-well structures

The electric-field-induced spin-orbit interaction (SOI) has been examined in double-sided doped quantum-well (QW) structures in which two different QWs of In_0.53Ga_0.47As (16 nm) or In_0.53Ga_0.47As (8 nm)/InAs (3 nm)/In_0.53Ga_0.47As (8 nm) are employed. Two separated carrier supply layers of different doping concentrations generate an asymmetric potential gradient in the QW, resulting in a structure-induced Rashba spin-splitting. By analyzing the Shubnikov-de Hass oscillation, the two different QWs are found to represent opposite SOI parameter (α) variations with respect to the gate electric field, which can be explained by the conduction band potential gradient and the charge distribution of the QWs. The InAs-inserted In_0.53Ga_0.47As QW exhibits an exclusively negative gradient while the In_0.53Ga_0.47As QW exhibits positive gradients on the side of the gate electrode.