Occurrence of superconductivity when the metal-insulator transition is inhibited in $1T$-TaS${_2}$

TL;DR

This study reveals that in 1T-TaS2, inhibiting the Mott transition with disorder induces an inhomogeneous superconducting state below 2.1 K, coexisting with charge-density-wave order, and is sensitive to magnetic fields.

Contribution

It demonstrates the emergence of superconductivity in a disordered, inhibited Mott transition in 1T-TaS2, linking bad metal states to superconductivity in layered dichalcogenides.

Findings

Superconductivity appears below 2.1 K when the Mott transition is inhibited.

Superconductivity coexists with nearly-commensurate charge-density-wave.

Superconductivity is suppressed by a magnetic field of 0.1 T.

Abstract

When a Mott metal-insulator transition is inhibited by a small amount of disorder in the layered dichalcogenide 1T-TaS$_2$, an inhomogeneous superconducting state arises below T=2.1 K, and coexists with a nearly-commensurate charge-density-wave. By angle-resolved photoelectron spectroscopy (ARPES) we show that it emerges from a bad metal state with strongly damped quasiparticles. Superconductivity is almost entirely suppressed by an external magnetic field of 0.1 T.