Nature of native atomic defects in ZrTe$_5$ and their impact on the low-energy electronic structure

TL;DR

This study investigates how different growth methods affect the atomic defects in ZrTe$_5$ and how these defects influence its low-energy electronic properties, combining microscopy, spectroscopy, and theoretical calculations.

Contribution

It identifies the main surface defects in ZrTe$_5$, quantifies their densities, and clarifies their role in the material's anomalous resistivity.

Findings

Te vacancies and Zr intercalations are the main surface defects.

Defect densities vary with growth methods.

Defects act as ionized centers affecting electronic behavior.

Abstract

Over the past decades, investigations of the anomalous low-energy electronic properties of ZrTe$_5$ have reached a wide array of conclusions. An open question is the growth method's impact on the stoichiometry of ZrTe$_5$ samples, especially given the very small density of states near its chemical potential. Here we report on high resolution scanning tunneling microscopy and spectroscopy measurements performed on samples grown via different methods. Using density functional theory calculations, we identify the most prevalent types of atomic defects on the surface of ZrTe$_5$, namely Te vacancies and intercalated Zr atoms. Finally, we precisely quantify their density and outline their role as ionized defects in the anomalous resistivity of this material.