Superconductivity emerging from suppressed large magnetoresistant state in WTe2

TL;DR

This study reports the emergence of superconductivity in WTe2 under high pressure, coinciding with the suppression of its large magnetoresistance, and suggests a possible Lifshitz transition related to changes in carrier populations.

Contribution

First observation of pressure-induced superconductivity in WTe2 near suppressed magnetoresistance without structural change, revealing a potential quantum phase transition.

Findings

Superconductivity appears at 10.5 GPa with no crystal structure change.

Maximum Tc of 6.5 K at around 15 GPa.

Sign change in Hall coefficient indicating a Lifshitz transition.

Abstract

The recent discovery of large and non-saturating magnetoresistance (LMR) in WTe2 provides a unique playground to find new phenomena and significant perspective for potential applications. Here we report the first observation of superconductivity near the proximity of suppressed LMR state in pressurized WTe2 through high-pressure synchrotron X-ray diffraction, electrical resistance, magnetoresistance, and ac magnetic susceptibility measurements. It is found that the positive magnetoresistance effect can be turned off at a critical pressure of 10.5 GPa without crystal structure change and superconductivity emerges simultaneously. The maximum superconducting transition temperature can be reached to 6.5 K at ~15 GPa and it decreases down to 2.6 K at ~25 GPa. In-situ high pressure Hall coefficient measurements at 10 K demonstrate that elevating pressure decreases hole carrier's population but increases electron carrier's population. Significantly, at the critical pressure, we observed a sign change in the Hall coefficient, indicating a possible Lifshitz-type quantum phase transition in WTe2.