TEMPERATURE-DEPENDENCE OF THE PHASE COHERENCE LENGTH OF HIGH-MOBILITY ALGAAS GAAS QUANTUM-WIRE RINGS

The temperature dependence of the phase coherence length, L-phi, 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 L-phi from the experimental AB oscillation amplitudes. The phase coherence time, tau-phi, was estimated from L-phi using an expression for an intermediated region. It was found that below 2.0 K, L-phi saturates at 2.5-mu-m and tau-phi saturates at 24 ps. The temperature dependence of tau-phi showed approximately T-2 dependence above 2.0 K, which is characteristic of electron-electron scattering in a pure system.