Pressure-induced shift of T$_c$ in K$_x$Sr$_{1-x}$Fe$_2$As$_2$ (x=0.2, 0.4, 0.7): Analogy to the high-T$_c$ cuprate superconductors

TL;DR

This study examines how pressure affects the critical temperature in K_xSr_{1-x}Fe_2As_2 superconductors across different compositions, revealing behaviors similar to high-T_c cuprates due to layered structures and charge transfer effects.

Contribution

It provides a systematic analysis of pressure effects on T_c in FeAs superconductors, highlighting similarities with cuprates and exploring the coexistence of superconductivity and spin-density waves.

Findings

Pressure shifts of T_c vary across compositions.

Layered structure influences pressure response.

Coexistence of superconductivity and spin-density wave observed.

Abstract

The systematic pressure shifts of T_c were investigated in the whole phase diagram of the FeAs-based superconducting compound K_xSr_{1-x}Fe_2As_2. Different regions, arising from corresponding responses of T$_c$ to pressure (dT_c/dp>0, =0, or <0), can be clearly distinguished. This reveals an interesting similarity of the FeAs superconductors and the high-T_c cuprates. This behavior is a manifestation of the layered structure of the FeAs compounds and the pressure-induced charge transfer between the (Fe_2As_2) and (K/Sr) layers. The coexistence of superconductivity and spin-density wave behavior were also observed, and the pressure effects on the latter is explored.