On the role of chalcogen vapor annealing in inducing bulk superconductivity in Fe${}_{1+y}$Te${}_{1-x}$Se${}_x$

Abstract

Recent investigations have shown that Fe${}_{1+y}$Te${}_{1-x}$Se${}_x$ can be made superconducting by annealing it in Se and O vapors. The current lore is that these chalcogen vapors induce superconductivity by removing the magnetic excess Fe atoms. To investigate this phenomenon we performed a combination of magnetic susceptibility, specific heat and transport measurements together with scanning tunneling microscopy and spectroscopy and density functional theory calculations on Fe${}_{1+y}$Te${}_{1-x}$Se${}_x$ treated with Te vapor. We conclude that the main role of the Te vapor is to quench the magnetic moments of the excess Fe atoms by forming FeTe${}_m$ (m $\ge$ 1) complexes. We show that the remaining FeTe${}_m$ complexes are still damaging to the superconductivity and therefore that their removal potentially could further improve superconductive properties in these compounds.

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Cited by in corpus (2)

• Correlation-Driven Electronic Reconstruction in FeTe${}_{1-x}$Se${}_x$
• Influence of interstitial Fe to the phase diagram of Fe${}_{1+y}$Te${}_{1-x}$Se${}_x$ single crystals