# Detection of charge density wave phase transitions at 1T-TaS$_2$/GaAs interfaces

## TL;DR

This study investigates how charge density wave (CDW) phase transitions in 1T-TaS$_2$ affect the electrical transport and capacitance at its interface with n-type GaAs, revealing significant changes in barrier properties.

## Contribution

It provides the first detailed analysis of how CDW transitions in 1T-TaS$_2$ influence interface barrier parameters with GaAs, using transport and capacitance measurements.

## Key findings

- Barrier parameters change across the CDW transition.
- Bond polarization model explains the barrier behavior.
- Decreased dielectric constant and increased potential drop observed.

## Abstract

The transition metal dichalcogenide 1T-TaS$_2$ is well known to harbor a rich variety of charge density wave (CDW) distortions which are correlated with underlying lattice atom modulations. The long range CDW phases extend throughout the whole crystal and terminate with charge displacements at the crystal boundaries. Here we report on the transport properties and capacitance characteristics of the interface between freshly exfoliated flakes of 1T-TaS$_2$ in intimate van der Waals contact with \textit{n}-type GaAs substrates. The extracted barrier parameters (ideality, barrier height and built-in potential) experience pronounced changes across the Mott-CDW transition in the 1T-TaS$_2$. The CDW-induced changes in barrier properties are well described by a bond polarization model which upon decreasing temperature gives rise to an increased potential drop across the interfacial region due to the localization of carriers and a decreased dielectric constant.