Two phase transitions driven by surface electron-doping in WTe$_2$

TL;DR

This study reveals two distinct phase transitions in WTe₂ induced by surface electron doping, involving structural shear and enhanced dopant-host interactions, which significantly alter its electronic properties.

Contribution

It uncovers two non-monotonic electronic structure changes in WTe₂ driven by in-situ electron doping, highlighting structural and interaction-driven phase transitions.

Findings

First transition involves shear displacement of the top layer.

Second transition involves hybridization and electric field effects.

Doping induces significant electronic and structural modifications.

Abstract

WTe$_2$ is a multifunctional quantum material exhibiting numerous emergent phases in which tuning of the carrier density plays an important role. Here we demonstrate two non-monotonic changes in the electronic structure of WTe$_2$ upon \textit{in-situ} electron doping. The first phase transition is interpreted in terms of a shear displacement of the top WTe$_2$ layer, which realizes a local crystal structure not normally found in bulk WTe$_2$. The second phase transition is associated with stronger interactions between the dopant atoms and the host, both through hybridization and electric field. These results demonstrate that electron-doping can drive structural and electronics changes in bulk WTe$_2$ with implications for realizing nontrivial band structure changes in heterointerfaces and devices.