Suppression of weak antilocalization in Ga_xIn_1−xAs∕InP narrow quantum wires

The magnetoconductivity of Ga_xIn_1−xAs∕InP quantum wires with widths in the range of 1220–250 nm was investigated. The finite zero-field spin splitting in our samples gives rise to spin relaxation and weak antilocalization in wide wires. In contrast, for the narrow wires, only weak-localization behavior is seen even though the zero-field spin splitting is independent of wire width. The observed renormalization of the spin-relaxation length due to purely geometrical effects can be described quantitatively using a model where the effect of spin precession is represented by spin-dependent pseudomagnetic fluxes, and by exact numerical transport calculations.