Superconductivity in the Hexagonal Ternary Phosphide ScIrP

TL;DR

This paper reports the discovery of superconductivity at 3.4 K in the noncentrosymmetric hexagonal ternary phosphide ScIrP, highlighting its weakly-coupled BCS nature, type-II behavior, and the influence of strong spin-orbit interaction.

Contribution

It is the first report of superconductivity in ScIrP, revealing its superconducting properties and electronic structure related to strong spin-orbit effects in a noncentrosymmetric crystal.

Findings

Superconducting transition at 3.4 K in ScIrP

Type-II superconductor with high upper critical field

Strong spin-orbit interaction influences superconductivity

Abstract

We report the discovery of a bulk superconducting transition at 3.4 K in the ternary phosphide, ScIrP, which crystallizes in a hexagonal ZrNiAl-type structure without spatial inversion symmetry. On the basis of heat capacity data in a zero magnetic field, ScIrP is suggested to be a weakly-coupled Bardeen-Cooper-Schrieffer superconductor. Alternatively, experimental results under magnetic fields indicate that this material is a type-II superconductor with an upper critical field Hc2 at magnetic fields above 5 T at zero temperature. This moderately high Hc2 does not violate the Pauli limit, but it does imply that there is a significant effect from the strong spin-orbit interaction of Ir 5d electrons in the noncentrosymmetric crystal structure. Electronic structure calculations show an interesting feature of ScIrP, where both the Sc 3d and Ir 5d orbitals contribute to the electronic density of states at the Fermi level.