Pair breaking by nonmagnetic impurities in the noncentrosymmetric superconductor CePt3Si

TL;DR

This study investigates how nonmagnetic impurities and pressure affect the superconductivity and magnetic order in the heavy-fermion superconductor CePt3Si, revealing impurity scattering as the main suppressor of superconductivity.

Contribution

It demonstrates that chemical disorder from Ge substitution primarily suppresses superconductivity through scattering, not volume change, in CePt3Si.

Findings

Superconductivity suppression is mainly due to impurity scattering.

Antiferromagnetic order remains unaffected by Ge-induced disorder.

Pressure effects are less significant than impurity scattering in suppressing superconductivity.

Abstract

We have studied the effect of Ge substitution and pressure on the heavy-fermion superconductor CePt3Si. Ge substitution on the Si site acts as negative chemical pressure leading to an increase in the unit-cell volume but also introduces chemical disorder. We carried out electrical resistivity and ac heat-capacity experiments under hydrostatic pressure on CePt3Si1-xGex (x=0, 0.06). Our experiments show that the suppression of superconductivity in CePt3Si1-xGex is mainly caused by the scattering potential, rather than volume expansion, introduced by the Ge dopants. The antiferromagnetic order is essentially not affected by the chemical disorder.