# Anticorrelation between polar lattice instability and superconductivity in the Weyl semimetal candidate MoTe2

## TL;DR

This study reveals that in MoTe2, suppressing polar lattice instability via pressure enhances superconductivity, highlighting the interplay between structural phases and superconducting properties in Weyl semimetals.

## Contribution

It demonstrates the inverse relationship between polar structural instability and superconductivity in MoTe2 using controlled physical and chemical pressure methods.

## Key findings

- Superconducting transition temperature Tc increases near the polar-to-nonpolar transition.
- Physical pressure more effectively suppresses polar transition and enhances Tc than chemical pressure.
- Modifications in phonon dispersion or band structure are linked to Tc enhancement.

## Abstract

The relation between the polar structural instability and superconductivity in a Weyl semimetal candidate MoTe2 has been clarified by finely controlled physical and chemical pressure. The physical pressure as well as the chemical pressure, i.e., the Se substitution for Te, enhances the superconducting transition temperature Tc at around the critical pressure where the polar structure transition disappears. From the heat capacity and thermopower measurements, we ascribe the significant enhancement of Tc at the critical pressure to a subtle modification of the phonon dispersion or the semimetallic band structure upon the polar-to-nonpolar transition. On the other hand, the physical pressure, which strongly reduces the interlayer distance, is more effective on the suppression of the polar structural transition and the enhancement of Tc as compared with the chemical pressure, which emphasizes the importance of the interlayer coupling on the structural and superconducting instability in MoTe2.