Critical Slowing Down of the Charge Carrier Dynamics at the Mott Metal-Insulator Transition

TL;DR

This paper investigates the critical slowing down of charge carrier dynamics near the Mott metal-insulator transition in a quasi-two-dimensional organic conductor, revealing divergence in resistance fluctuations and non-Gaussian behavior indicative of glassy electronic states.

Contribution

It provides experimental evidence of critical slowing down and non-Gaussian fluctuations at the Mott transition, suggesting glassy electronic behavior as a precursor.

Findings

Divergent resistance fluctuations at the critical endpoint

Spectral weight shifts to low frequencies indicating slow dynamics

Non-Gaussian fluctuations suggest correlated charge carrier behavior

Abstract

We report on the dramatic slowing down of the charge carrier dynamics in a quasi-two-dimensional organic conductor, which can be reversibly tuned through the Mott metal-insulator transition (MIT). At the finite-temperature critical endpoint we observe a divergent increase of the resistance fluctuations accompanied by a drastic shift of spectral weight to low frequencies, demonstrating the critical slowing down of the order parameter (doublon density) fluctuations. The slow dynamics is accompanied by non-Gaussian fluctuations, indicative of correlated charge carrier dynamics. A possible explanation is a glassy freezing of the electronic system as a precursor of the Mott MIT.