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

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.