Phase coherence length of electron waves in narrow AlGaAs/GaAs quantum wires fabricated by focused ion beam implantation

Abstract

The phase coherence length Lφ of electron waves in the one-dimensional weak localization regime was studied in selectively doped AlGaAs/GaAs quantum wires fabricated by focused ion beam implantation. Estimated Lφ by fitting the modified weak localization theory to the data is ∼1.2 μm at 0.3 K, nine times longer than in the n-GaAs wires. This difference is well explained by the mobility dependence of Lφ, and shows the advantage of selectively doped structures to obtain long Lφ. Lφ increased with decreasing temperature and saturated below ∼3 K, indicating the existence of temperature-independent phase breaking mechanisms.