High-pressure single-crystal neutron scattering study of magnetic and Fe vacancy orders in (Tl,Rb)2Fe4Se5 superconductor

TL;DR

This study uses high-pressure neutron diffraction to explore how magnetic and Fe vacancy orders in (Tl,Rb)2Fe4Se5 superconductors change under pressure, revealing their relationship with superconductivity and phase transitions.

Contribution

It provides new insights into the pressure-dependent behavior of magnetic and vacancy orders in (Tl,Rb)2Fe4Se5, linking these to superconductivity and phase stability.

Findings

Magnetic order decreases with pressure but remains until a critical point

Fe vacancy order remains stable until a sudden disappearance at 8.3 GPa

Superconductivity coexists with magnetic and vacancy orders within a certain pressure range

Abstract

The magnetic and iron vacancy orders in superconducting (Tl,Rb)2Fe4Se5 single-crystals are investigated by using a high-pressure neutron diffraction technique. Similar to the temperature effect, the block antiferromagnetic order gradually decreases upon increasing pressure while the Fe vacancy superstructural order remains intact before its precipitous disappearance at the critical pressure Pc = 8.3 GPa. Combined with previously determined Pc for superconductivity, our phase diagram under pressure reveals the concurrence of the block AFM order, the iron vacancy order and superconductivity for the 245 superconductor. A synthesis of current experimental data in a coherent physical picture is attempted.