Superconducting ground state of nonsymmorphic superconducting compound Zr$_{2}$Ir

TL;DR

This study investigates Zr$_{2}$Ir, a nonsymmorphic superconductor, revealing it has a conventional s-wave ground state with preserved time-reversal symmetry and isotropic superconducting gap, despite its topological semimetal candidate status.

Contribution

It provides the first detailed experimental characterization of Zr$_{2}$Ir's superconducting properties, confirming its conventional s-wave nature and symmetry preservation.

Findings

Superconducting transition temperature of 7.4 K.

Critical fields of 19.6 mT and 3.79 T.

Preservation of time-reversal symmetry and isotropic gap.

Abstract

The nonsymmorphic Zr$_{2}$Ir alloy is a possible topological semimetal candidate material and as such may be part of an exotic class of superconductors. Zr$_{2}$Ir is a superconductor with a transition temperature of 7.4 K with critical fields of 19.6(3) mT and 3.79(3) T, as determined by heat capacity and magnetisation. Zero field muon spin relaxation measurements show that time-reversal symmetry is preserved in these materials. The specific heat and transverse field muon spin rotation measurements rule out any possibility to have a nodal or anisotropic superconducting gap, revealing a conventional s-wave nature in the superconducting ground state. Therefore, this system is found to be conventional nonsymmorphic superconductor, with time-reversal symmetry being preserved and an isotropic superconducting gap.