Rashba effect in gated InGaAs/InP quantum wire structures

The effect of Rashba spin–orbit coupling is investigated in gated quantum wire structures of various widths. The quantum wires are based on a strained InGaAs/InP heterostructure. A clear beating pattern in the magnetoresistance due to Rashba spin–orbit coupling is observed for wires as narrow as View the MathML source. The characteristic node of the beating pattern is shifted towards larger magnetic fields for decreasing widths of the wires. It is found that the Rashba coupling parameter does not change significantly if the carrier concentration is varied by a gate voltage. The difference in the oscillation patterns of the wire structures compared to the two-dimensional structure is explained by the additional energy contribution due to the geometrical confinement in the wires.