Pressure study of the noncentrosymmetric 5d-electron superconductors CaMSi3 (M= Ir, Pt)

TL;DR

This study investigates how hydrostatic pressure affects the superconducting properties of noncentrosymmetric CaMSi3 (M= Ir, Pt), revealing a decrease in critical temperature linked to changes in electron-phonon interactions and density of states.

Contribution

It provides the first detailed pressure-dependent resistivity and Tc measurements for CaMSi3 superconductors, highlighting the role of electron-phonon scattering and density of states in their superconductivity.

Findings

Resistivity follows Bloch-Grüneisen behavior under pressure

Superconducting Tc decreases with pressure at ~0.2 K/GPa

Tc decrease explained by reduced density of states in BCS framework

Abstract

We report hydrostatic pressure study on the Rashba-type noncentrosymmetric superconduc- tors CaMSi3 (M= Ir, Pt). The temperature dependence of the resistivity for both compounds is well described by the conventional Bloch-Gr\"uneisen formalism at each pressure. This fact suggests that electron-phonon scattering is dominant in these compounds. The superconducting critical temperature Tc decreases by pressure as \sim 0.2 K/GPa above 0.41 GPa to 2 GPa for both compounds. This behavior of Tc can be explained with a modest decrease of the density of states based on the conventional BCS theory.