Saturation of phase coherence length in GaAs/AlGaAs on-facet quantum wires

Abstract

Phase coherence length Lφ of on-facet quantum wires is determined at temperatures down to 50 mK by three methods: magnetoresistance, conductance fluctuation amplitude, and the conductance fluctuation correlation field. It is found that Lφ saturates below about 0.4 K. This saturation is identified as due to spin-orbit interaction, which has no temperature dependence. This result is supported by positive magnetoresistance under a weak magnetic field.