Electronic Phase Diagram of SrFe$_2$(As$_{1-x}$P$_x$)$_2$: Effect of Structural Dimensionality

TL;DR

This study maps the electronic phase diagram of SrFe₂(As₁₋ₓPₓ)₂, revealing that superconductivity is more influenced by pnictogen height than by Fermi surface dimensionality, with postannealing enhancing superconducting properties.

Contribution

It demonstrates that structural dimensionality has less impact on superconductivity than pnictogen height in SrFe₂(As₁₋ₓPₓ)₂, supported by phase diagram and electronic property analysis.

Findings

Postannealing reduces residual resistivity and raises T_c to 33 K.

Phase diagram similar to BaFe₂(As₁₋ₓPₓ)₂ despite different lattice constants.

Superconductivity more dependent on pnictogen height than Fermi surface dimensionality.

Abstract

We have investigated the electronic properties of SrFe$_2$(As$_{1-x}$P$_x$)$_2$ ($0\leqq x\leqq1$) single crystals with postannealing treatment and established a phase diagram of this system. The postannealing treatment reduced the residual resistivity in an antiferromagnetic-orthorhombic phase and enhanced the superconducting transition temperature to $T_{c, optimal}$=33\,K in the superconducting phase. The obtained phase diagram and electronic properties are similar to those of BaFe$_2$(As$_{1-x}$P$_x$)$_2$ despite the large difference in lattice constants. This indicates that, for superconductivity, the dimensionality of the Fermi surface determined by the crystal structural anisotropy is less important than the pnictogen height from the Fe plane.