Superconductivity with the enhanced upper critical field in the Pt-Doping CuRh2Se4 spinel

TL;DR

This study explores how Pt doping affects superconductivity in CuRh2Se4 spinel, revealing an enhanced upper critical field and a dome-shaped Tc with theoretical insights into electronic structure changes.

Contribution

It provides combined experimental and theoretical evidence on the effects of Pt doping, including critical field enhancement and electronic structure modifications, in CuRh2Se4 superconductors.

Findings

Maximum Tc of 3.84 K at x=0.06

Significant increase in upper critical magnetic field to 4.93 T

Pt doping induces a red-shift in the density of states peak near the Fermi level

Abstract

We report the effect of Pt doping on the superconductivity in CuRh2Se4 spinel using a combined experimental and theoretical study. Our XRD results reveal that the Cu(Rh1-xPtx)2Se4 crystallizes in the structure with a space group of Fd3-m (No. 227), and the lattice parameter a increases with Pt doping. The resistivity and magnetic susceptibility measurement results verify that the superconducting transition temperature (Tc) forms a dome-like shape with a maximum value of 3.84 K at x = 0.06. It is also observed that the Pt-doping slightly reduces the lower critical magnetic field from 220 Oe in CuRh2Se4 to 168 Oe in Cu(Rh0.94Pt0.06)2Se4, while it significantly enhances the upper critical magnetic field, reaching the maximum of 4.93 T in the Cu(Rh0.94Pt0.06)2Se4 sample. The heat capacity result indicates that the sample Cu(Rh0.91Pt0.09)2Se4 is a bulk superconductor. First-principles calculations suggest that the Pt-doping leads to a red-shift of a density of state peak near the Fermi level, consistent with the dome-like Tc observed experimentally.