Superconductivity close to magnetic instability in Fe(Se1-xTex)0.82

TL;DR

This study explores how superconductivity evolves in Fe(Se1-xTex)0.82, revealing a new superconducting phase linked to magnetic fluctuations and suggesting unconventional superconductivity near magnetic instability.

Contribution

It reports the discovery of a new superconducting phase in Fe(Se1-xTex)0.82 and analyzes its relationship with magnetic order and fluctuations.

Findings

New superconducting phase with Tc up to 14 K identified.

Superconductivity suppressed near FeTe0.82 with magnetic order.

Superconductivity likely related to magnetic fluctuations, indicating unconventional behavior.

Abstract

We report our study of the evolution of superconductivity and the phase diagram of the ternary Fe(Se1-xTex)0.82 (0<=x<=1.0) system. We discovered a new superconducting phase with Tc,max = 14 K in the 0.3 < x < 1.0 range. This superconducting phase is suppressed when the sample composition approaches the end member FeTe0.82, which exhibits an incommensurate antiferromagnetic order. We discuss the relationship between the superconductivity and magnetism of this material system in terms of recent results from neutron scattering measurements. Our results and analyses suggest that superconductivity in this new class of Fe-based compounds is associated with magnetic fluctuations, and therefore may be unconventional in nature.