Systematic study of superconductivity in few-layer $T_d$-MoTe$_2$

TL;DR

This study systematically explores superconductivity in few-layer $T_d$-MoTe$_2$, revealing how disorder, doping, and band structure influence $T_c$, and demonstrating conventional phonon-mediated pairing in highly hole-doped regimes.

Contribution

It provides a comprehensive experimental and theoretical analysis of superconductivity in few-layer $T_d$-MoTe$_2$, including new insights into highly hole-doped regimes and their pairing mechanisms.

Findings

Superconducting $T_c$ correlates with disorder, doping, and mobility.

Superconductivity in highly hole-doped 2L samples is consistent with phonon-mediated $s_{(++)}$-wave pairing.

First-principles calculations link band structure features to superconducting behavior.

Abstract

We present a systematic investigation of superconductivity in a topological superconductor candidate $T_{\rm d}$-MoTe$_2$ in the few-layer limit. By examining multiple mechanically exfoliated samples with different thicknesses, substrates and crystal qualities, we quantitatively correlate superconducting temperature ($T_c$) with disorder, carrier density, carrier type and mobility. By integrating these experimental findings with first-principles calculations, we reveal the relationship between the band structure and superconductivity in this material. Notably, in 2 L samples we access a highly hole-doped regime that has not been systematically explored in previous experiments, providing a complementary perspective to earlier studies. In this regime, we demonstrate that superconductivity can be realized in a manner consistent with a conventional phonon-mediated $s_{(++)}$-wave pairing.