Electron dephasing near zero temperature: an experimental review

TL;DR

This review discusses the experimental status of electron dephasing time near zero temperature, focusing on whether it diverges or saturates, and highlights unresolved questions about the causes of observed saturation effects.

Contribution

It provides a comprehensive overview of recent experimental findings on electron dephasing times and the ongoing debate about their behavior at very low temperatures.

Findings

Evidence of weak temperature dependence of dephasing time at low T

Saturation of dephasing time observed in multiple experiments

The origins of saturation effects remain unresolved

Abstract

The behavior of the electron dephasing time near zero temperature, $\tau_\phi^0$, has recently attracted vigorous attention. This renewed interest is primarily concerned with whether $\tau_\phi^0$ should reach a finite or an infinite value as $T \to$ 0. While it is accepted that $\tau_\phi^0$ should diverge if there exists only electron-electron (electron-phonon) scattering, several recent measurements have found that $\tau_\phi^0$ depends only very weakly on temperature, if at all, when $T$ is sufficiently low. This article discusses the current experimental status of "the saturation problem", and concludes that the origin(s) for this widely observed saturation are still unresolved.