Channel width effect on the spin-orbit interaction parameter in a two-dimensional electron gas

The spin splitting energy obtained from the Shubnikov–de Haas oscillation increases with decreasing channel width (w) of the InAs-based heterostructure. Since the surface charge concentration depends only weakly on w, the channel width dependence of the spin splitting energy is attributed to variations in the spin-orbit interaction strength. The spin-orbit interaction parameter was found to be inversely proportional to w in the range of w=2–64μm. Our findings indicate that a strong spin-orbit interaction is induced in a narrow channel due to suppression of the spin precession length for a thin quantum well layer system.