Local resilience of the $1T$-TiSe$_2$ charge density wave to Ti self-doping

TL;DR

This study investigates how the charge density wave in Ti-intercalated $1T$-TiSe$_2$ crystals responds locally to Ti self-doping, revealing a resilience mechanism that maintains the CDW despite doping-induced disruptions.

Contribution

It uncovers a dopant-site dependence of the CDW gap and demonstrates a local resilience mechanism in the CDW of $1T$-TiSe$_2$ through combined experimental and theoretical analysis.

Findings

CDW gap depends on dopant site

Long-range phase coherence loss does not close the CDW gap

Resilience mechanism limits the impact of Ti doping on CDW

Abstract

In Ti-intercalated self-doped $1T$-TiSe$_2$ crystals, the charge density wave (CDW) superstructure induces two nonequivalent sites for Ti dopants. Recently, it has been shown that increasing Ti doping dramatically influences the CDW by breaking it into phase-shifted domains. Here, we report scanning tunneling microscopy and spectroscopy experiments that reveal a dopant-site dependence of the CDW gap. Supported by density functional theory, we demonstrate that the loss of the longrange phase coherence introduces an imbalance in the intercalated-Ti site distribution and restrains the CDW gap closure. This local resilient behavior of the $1T$-TiSe$_2$ CDW reveals a novel mechanism between CDW and defects in mutual influence.