Dephasing Time in a Two-Dimensional Electron Fermi Liquid

TL;DR

This study measures the low-temperature dephasing time in a two-dimensional electron Fermi liquid using weak localization, finding no saturation down to 100mK and extrapolating a zero-temperature dephasing time over 4ns.

Contribution

It introduces a novel temperature calibration method based on the integer quantum Hall effect and confirms theoretical predictions for dephasing in 2D electron systems.

Findings

Dephasing time exceeds 4ns at zero temperature.

No saturation of dephasing time observed down to 100mK.

Results agree with recent theoretical models.

Abstract

The observation of coherent quantum transport phenomena in metals and semiconductors is limited by the eventual loss of phase coherence of the conducting electrons. We use the weak localization effect to measure the low-temperature dephasing time in a two-dimensional electron Fermi liquid in GaAs/AlGaAs heterostructures. We use a novel temperature calibration method based on the integer quantum Hall effect in order to directly measure the electrons' temperature. The data are in excellent agreement with recent theoretical results, including contributions from the triplet channel, for a broad temperature range. We see no evidence for saturation of the dephasing time down to around 100mK. Moreover, the zero-temperature dephasing time is extrapolated to be higher than 4ns.