Tip-induced Superconductivity Coexisting with Preserved Topological Properties in Line-nodal Semimetal ZrSiS

TL;DR

This study demonstrates that a non-superconducting metallic tip can induce a high-temperature superconducting phase in ZrSiS, a topological semimetal, while preserving its topological properties, combining topological and superconducting features.

Contribution

It reveals that tip-induced superconductivity can be achieved in ZrSiS without destroying its topological characteristics, supported by first-principles calculations.

Findings

Superconductivity with T_c of 7.5 K induced by Ag tip.

Topological properties of ZrSiS remain intact under tip-induced superconductivity.

Superconducting phase likely results from increased density of states due to the metallic tip.

Abstract

ZrSiS was recently shown to be a new material with topologically non-trivial band structure which exhibits multiple Dirac nodes and a robust linear band dispersion up to an unusually high energy of 2\,eV. Such a robust linear dispersion makes the topological properties of ZrSiS insensitive to perturbations like carrier doping or lattice distortion. Here we show that a novel superconducting phase with a remarkably high $T_c$ of 7.5\,K can be induced in single crystals of ZrSiS by a non-superconducting metallic tip of Ag. From first-principles calculations we show that the observed superconducting phase might originate from dramatic enhancement of density of states due to the presence of a metallic tip on ZrSiS. Our calculations also show that the emerging tip-induced superconducting phase co-exists with the well preserved topological properties of ZrSiS.