Interplay of Defects and the Charge Density Wave State in Hf-Doped ZrTe$_{3}$

TL;DR

This study uses STM and DFT to investigate how defects, mainly Te and Zr vacancies, influence the charge density wave state in Hf-doped ZrTe3, revealing defect-related pinning effects across the CDW transition.

Contribution

The paper combines STM and DFT to identify defect types in Hf-doped ZrTe3 and explores their impact on the CDW state, providing new insights into defect-CDW interactions.

Findings

Defects are mainly Te and Zr vacancies, not Hf dopants.

CDW pinning occurs at both defect types below and above T_CDW.

No clear electronic signatures directly linked to Hf dopants.

Abstract

We carry out temperature-dependent scanning tunneling microscopy (STM) studies of the charge density wave (CDW) compound ZrTe$_3$ which is intentionally doped with Hf. Previous bulk studies tie Hf doping to an enhancement of the CDW transition temperature (T$_{CDW}$). In our work, by combining STM measurements with density functional theory (DFT) calculations, we observe and identify multiple defects in Zr$_{0.95}$Hf$_{0.05}$Te$_3$. Surprisingly, instead of finding clear structural or electronic signatures associated with Hf dopants, we determine the origin of the observed defects are consistent with Te and Zr vacancies. Further, our temperature dependent STM measurements allow us to examine CDW pinning to both types of observed defects below and above T$_{CDW}$.