Substitution Effects on FeSe Superconductor

TL;DR

This study explores how atomic substitutions in FeSe affect its superconducting transition temperature, revealing that S and Te increase Tc while Co and Ni suppress it, providing insights into tuning superconductivity.

Contribution

It provides a detailed analysis of substitution effects in FeSe, highlighting how different elements influence superconductivity and offering a methodology for Tc measurement.

Findings

S substitution increases Tc by up to 20%

Te substitution increases Tc by up to 75%

Co and Ni substitutions suppress superconductivity

Abstract

We have investigated the effect of atomic substitutions in the FeSe system, which exhibits the simplest crystal structure among the iron-based superconductors. An enhancement of the superconducting transition temperature Tc was observed with the substitution of S or Te for Se; the Tc increased with S substitution by up to 20 %, and also increased with Te substitution up to 75 %. In contrast, Co or Ni substitutions for the Fe site significantly suppressed superconductivity. In this work we present a detailed description of the substitution technique employed to determine Tc in the FeSe system.