AHARONOV-BOHM EFFECT IN QUASI-ONE-DIMENSIONAL IN0.77GA0.23AS/INP RINGS

Aharonov-Bohm oscillations with a modulation of the resistance amplitude up to 12% have been observed in high mobility ${\mathrm{In}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Ga}}_{\mathit{x}}$As/InP rings. The phase coherence length ${\mathit{L}}_{\mathrm{\ensuremath{\Phi}}}$ is extracted from the interference pattern by an analysis of the oscillation amplitude as a function of temperature and electron excess energy. ${\mathit{L}}_{\mathrm{\ensuremath{\Phi}}}$ shows approximately a ${\mathit{T}}^{\mathrm{\ensuremath{-}}0.5}$ dependence for temperatures between 2 and 10 K. We attribute this behavior to momentum-nonconserving processes in a quasi-one-dimensional ring structure. Although the widths of the samples are comparable to the Fermi wavelength there is still more than one one-dimensional conducting channel in the ring and the phase coherence length saturates for decreasing temperature.