Structural study on hole-doped superconductors Pr1-xSrxFeAsO

TL;DR

This study investigates how hole doping with Sr affects the structure and superconductivity in Pr1-xSrxFeAsO, revealing the importance of interlayer spacing for Tc enhancement in Fe-based superconductors.

Contribution

It provides detailed structural analysis of Pr1-xSrxFeAsO across doping levels and highlights the role of interlayer space in superconductivity, differing from electron-doped systems.

Findings

Superconductivity appears at Sr doping of 0.221.

Lattice constants increase linearly with Sr doping.

Interlayer space influences Tc in hole-doped systems.

Abstract

The structural details in Pr1-xSrxFeAsO (1111) superconducting system are analyzed using data obtained from synchrotron X-ray diffraction and the structural parameters are carefully studied as the system is moving from non-superconducting to hole-doped superconducting with the Sr concentration. Superconductivity emerges when the Sr doping amount reaches 0.221. The linear increase of the lattice constants proves that Sr is successfully introduced into the system and its concentration can accurately be determined by the electron density analyses. The evolution of structural parameters with Sr concentration in Pr1-xSrxFeAsO and their comparison to other similar structural parameters of the related Fe-based superconductors suggest that the interlayer space between the conducting As-Fe-As layer and the insulating Pr-O-Pr layer is important for improving Tc in the hole-doped (1111) superconductors, which seems to be different from electron-doped systems.