Strong Electronic Interaction and Signatures of Nodal Superconductivity in Zr$_5$Pt$_3$C$_x$

TL;DR

This study investigates Zr$_5$Pt$_3$C$_x$ revealing strong electronic interactions and signatures of unconventional nodal superconductivity, with doping significantly affecting its electronic properties and superconducting behavior.

Contribution

It provides the first detailed electronic structure analysis of Zr$_5$Pt$_3$C$_x$ showing complex Fermi surfaces and unconventional superconductivity signatures.

Findings

Enhanced electron-electron interactions with C doping

Unconventional superconductivity indicated by critical field behavior

Deviation from s-wave BCS pairing in temperature dependence

Abstract

The physical properties of the Zr$_5$Pt$_3$ compound with interstitial carbon in hexagonal D8$_8$-structure was investigated. A set of macroscopic measurements reveal a bulk superconducting at approximately 7 K for Zr$_5$Pt$_3$C$_{0.3}$ close to Zr$_5$Pt$_3$, also with a correlate anomalous resistivity behavior. However, both the signatures of strong electron-electron interaction, and the electronic contribution to specific heat, increase dramatically with the C doping. For the first time the x-ray photoelectron spectra compared with DFT/PWLO calculations of electronic structure show a complex Fermi surface with high density of states for Zr$_5$Pt$_3$. Also results show the signature of unconventional superconductivity. Indeed, was observed an unusual behavior for lower and upper critical field diagrams of Zr$_5$Pt$_3$C$_{0.3}$. The temperature dependence of penetration length and electronic contribution to specific heat suggests that electronic pairing deviates of $s$-wave the BCS scenario.