Conductance Fluctuations and Domain Depinning in Quasi-2D Charge-Density-Wave 1T-TaS$_2$ Thin Films

TL;DR

This study explores how conductance fluctuations and charge-density-wave domain depinning in 1T-TaS$_2$ thin films depend on temperature and thickness, revealing surface pinning effects and depinning mechanisms relevant for quantum material devices.

Contribution

It provides new insights into the temperature and thickness dependence of charge-density-wave depinning and conductance fluctuations in quasi-2D 1T-TaS$_2$ thin films.

Findings

Depinning threshold field increases as temperature decreases.

Thinner films exhibit higher depinning threshold fields.

Depinning is driven by electric field and local heating, absent in the commensurate phase.

Abstract

We investigated the temperature dependence of the conductance fluctuations in thin films of the quasi-two-dimensional 1T-TaS$_2$ van der Waals material. The conductance fluctuations, determined from the derivative current-voltage characteristics of two-terminal 1T-TaS$_2$ devices, appear prominently at the electric fields that correspond to the transitions between various charge-density-wave macroscopic quantum condensate phases and at the onset of the depinning of the charge density wave domains. The depinning threshold field, $E_D$, monotonically increases with decreasing temperature within the nearly commensurate charge-density-wave phase. The $E_D$ value increases with the decreasing 1T-TaS$_2$ film thickness, revealing the surface pinning of the charge density waves. Our analysis suggests that depinning is absent in the commensurate phase. It is induced by the electric field but facilitated by local heating. The measured trends for $E_D$ of the domain depinning are important for understanding the physics of charge density waves in quasi-two-dimensional crystals and for developing electronic devices based on this type of quantum materials.