Field induced hysteretic structural phase switching and possible CDW in Re-doped MoTe$_2$

TL;DR

This study reveals that Re doping in MoTe$_2$ induces a hysteretic phase switch and suggests the emergence of a charge density wave, with evidence of electric field-induced hysteretic behavior indicating piezoelectricity or ferroelectricity.

Contribution

It demonstrates for the first time that Re doping causes hysteretic structural phase switching and possibly a charge density wave in MoTe$_2$, expanding understanding of doped topological materials.

Findings

Re doping induces a possible charge density wave in MoTe$_2$.

Hysteresis observed in tunneling I-V characteristics and tip-height changes.

Electric field induces hysteretic switching consistent with piezoelectricity or ferroelectricity.

Abstract

Novel electronic systems displaying exotic physical properties can be derived from complex topological materials through chemical doping. MoTe$_2$, the candidate type-II Weyl semimetal shows dramatically enhanced superconductivity up to 4.1 K upon Re doping in Mo sites. Based on bulk transport and local scanning tunneling microscopy (STM) here we show that Re doping also leads to the emergence of a possible charge density wave (CDW) phase in Re$_{0.2}$Mo$_{0.8}$Te$_2$. In addition, the tunneling $I-V$ characteristics display non-linearity and hysteresis which is commensurate with a hysteresis observed in the change in tip-height ($z$) as a function of applied voltage $V$. The observations indicate an electric field induced hysteretic switching consistent with piezoelectricity and possible ferroelectricity.