Superfluid density and superconducting gaps of RbFe_{2}As_{2} as a function of hydrostatic pressure

TL;DR

This study investigates how hydrostatic pressure affects the superfluid density and superconducting gaps in RbFe_{2}As_{2}, revealing a significant decrease in T_{c} and the suppression of the smaller superconducting gap with increasing pressure.

Contribution

It provides detailed measurements of microscopic superconducting parameters of RbFe_{2}As_{2} under pressure, highlighting the pressure-induced suppression of superconductivity and gap features.

Findings

T_{c} decreases by 52% at 1 GPa pressure

Superconducting gaps decrease with pressure, with the smaller gap disappearing at 1 GPa

Superfluid density follows a two-gap s-wave model under pressure

Abstract

The superfluid density and superconducting gaps of superconducting RbFe_{2}As_{2} have been determined as a function of temperature, magnetic field and hydrostatic pressure by susceptibility and muon-spin spectroscopy measurements. From the data, fundamental microscopic parameters of the superconducting state like the London penetration depth \lambda, the gap values \Delta, the upper critical field B_{c2}, and the Ginzburg-Landau parameter \kappa have been obtained. In accordance with earlier measurements the ratio of the superfluid density n_{s} \propto \lambda^{-2} to the superconducting transition temperature T_{c}=2.52(2) K at ambient pressure is found to be much larger in the strongly hole-overdoped RbFe_{2}As_2 than in high-T_{c} Fe-based and other unconventional superconductors. As a function of pressure T_{c} strongly decreases with a rate of dT_{c}/dp = -1.32 K/GPa, i.e. it is reduced by 52 % at p = 1 GPa. The temperature dependence of n_{s} is best described by a two gap s-wave model with both superconducting gaps being decreased by hydrostatic pressure until smaller gap completely disappears at p = 1 GPa.