Charge density wave and superconductivity competition in Lu$_5$Ir$_4$Si$_{10}$ : a proton irradiation study

TL;DR

This study uses proton irradiation to investigate the competition between charge density waves and superconductivity in Lu$_5$Ir$_4$Si$_{10}$, revealing that disorder suppresses CDW while enhancing superconductivity, providing insights into their interplay.

Contribution

It demonstrates that proton irradiation-induced disorder can tune the balance between CDW and superconductivity, offering a new approach to study their competition in complex materials.

Findings

Disorder enhances superconducting critical temperature $T_c$ and $H_{c2}$.

Disorder suppresses the charge density wave (CDW).

Superconductivity and CDW compete for electronic density of states.

Abstract

Real-space modulated Charge Density Waves (CDW) are an ubiquituous feature in many families of superconductors. In particular, how CDW relates to superconductivity is an active and open question that has recently gathered much interest since CDWs have been discovered in many cuprates superconductors. Here we show that disorder induced by proton irradiation is a full-fledged tuning parameter that can bring essential information to answer this question as it affects CDW and superconductivity with different and unequivocal mechanisms. Specifically, in the model CDW superconductor Lu$_5$Ir$_4$Si$_{10}$ that develops a 1D CDW below 77\,K and s-wave superconductivity below 4\,K, we show that disorder enhances the superconducting critical temperature $T_\mathrm{c}$ and $H_\mathrm{c2}$ while it suppresses the CDW. Discussing how disorder affects both superconductivity and the CDW, we make a compelling case that superconductivity and CDW are competing for electronic density of states at the Fermi level in Lu$_5$Ir$_4$Si$_{10}$, and we reconcile the results obtained via the more common tuning parameters of pressure and doping. Owing to its prototypical, 1D, Peierls type CDW and the s-wave, weak-coupling nature of its superconductivity, this irradiation study of Lu$_5$Ir$_4$Si$_{10}$ provides the basis to understand and extend such studies to the more complex cases of density waves and superconductivity coexistence in heavy fermions, Fe-based or cuprates superconductors.