Superconductivity enhancement in the S-doped Weyl semimetal candidate MoTe2

TL;DR

This study demonstrates that partial sulfur substitution in MoTe2 significantly enhances its superconducting transition temperature, revealing a dome-shaped phase diagram and suggesting improved electron-phonon coupling as the underlying mechanism.

Contribution

It reports the first significant enhancement of superconductivity in MoTe2 via S doping, establishing a new platform for exploring topological and superconducting phenomena in TMDs.

Findings

Superconducting temperature (Tc) increased from 0.1 K to 1.3 K with S doping.

Superconductivity exhibits a dome-shaped phase diagram in S-doped MoTe2.

Enhanced electron-phonon coupling likely drives the Tc increase.

Abstract

Two-dimensional (2D) transition-metal dichalcogenide (TMDs) MoTe2 has attracted much attention due to its predicted Weyl semimetal (WSM) state and a quantum spin Hall insulator in bulk and monolayer form, respectively. We find that the superconductivity in MoTe2 single crystal can be much enhanced by the partial substitution of the Te ions by the S ones. The maximum of the superconducting temperature TC of MoTe1.8S0.2 single crystal is about 1.3 K. Compared with the parent MoTe2 single crystal (TC=0.1 K), nearly 13-fold in TC is improved in MoTe1.8S0.2 one. The superconductivity has been investigated by the resistivity and magnetization measurements. MoTe2-xSx single crystals belong to weak coupling superconductors and the improvement of the superconductivity may be related to the enhanced electron-phonon coupling induced by the S-ion substitution. A dome-shape superconducting phase diagram is obtained in the S-doped MoTe2 single crystals. MoTe2-xSx materials may provide a new platform for our understanding of superconductivity phenomena and topological physics in TMDs.