Temperature Dependence of the Phase Coherence Length of High-Mobility AlGaAs/GaAs Quantum-Wire Rings

The temperature dependence of the phase coherence length, Lφ, of high-mobility AlGaAs/GaAs quantum-wire rings was investigated through the Aharonov-Bohm (AB) magnetoresistance oscillations. The expression of the AB oscillation amplitude for the quasiballistic, multitransverse-mode quantum-wire rings was derived and used to extract Lφ from the experimental AB oscillation amplitudes. The phase coherence time, τφ, was estimated from Lφ using an expression for an intermediated region. It was found that below 2.0 K, Lφ saturates at 2.5 µm and τφ saturates at 24 ps. The temperature dependence of τφ showed approximately T-2 dependence above 2.0 K, which is characteristic of electron-electron scattering in a pure system.