Superconductivity induced by doping Rh in CaFe2-xRhxAs2

TL;DR

This study reports the successful synthesis of Rh-doped CaFe2As2 superconductors, showing that Rh doping suppresses SDW order and induces superconductivity with a maximum Tc of 18.5 K, expanding understanding of doping effects in iron-based superconductors.

Contribution

It demonstrates the induction of superconductivity in CaFe2As2 via Rh doping and compares phase diagrams with similar Rh-doped systems, highlighting the doping's impact on structural and magnetic properties.

Findings

Superconductivity achieved at 18.5 K with x=0.15 Rh doping.

Rh doping suppresses spin-density-wave transition.

Phase diagram similar to Rh-doped Sr122 system.

Abstract

In this paper we report the synthesis of iron-based superconductors CaFe2-xRhxAs2 using one-step solid state reaction method, which crystallizes in the ThCr2Si2-type structure with a space group I4/mmm. The systematic evolution of the lattice constants demonstrates that the Fe ions are successfully replaced by the Rh. By increasing the doping content of Rh, the spin-density-wave (SDW) transition in the parent compound is suppressed and superconductivity emerges. The maximum superconducting transition temperature is found at 18.5 K with the doping level of x = 0.15. The temperature dependence of DC magnetization confirms superconducting transitions at around 15 K. The general phase diagram was obtained and found to be similar to the case of Rh-doping Sr122 system. Our results explicitly demonstrate the feasibility of inducing superconductivity in Ca122 compounds by higher d-orbital electrons doping, however, different Rh-doping effect between FeAs122 compounds and FeAs1111 systems still remains an open question.