Quantum conductance-temperature phase diagram of granular superconductor K x Fe2−y Se2

Abstract It is now well established that the microstructure of Fe-based chalcogenide K x Fe2−y Se2 consists of, at least, a minor (~15 percent), nano-sized, superconducting K s Fe2Se2 phase and a major (~85 percent) insulating antiferromagnetic K2Fe4Se5 matrix. Other intercalated A 1−x Fe2−y Se2 (A...

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Autores principales:	C. C. Soares, M. ElMassalami, Y. Yanagisawa, M. Tanaka, H. Takeya, Y. Takano
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2018
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/8fedace8620d45d7a7b0fe7c5c9a0667
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spelling	oai:doaj.org-article:8fedace8620d45d7a7b0fe7c5c9a06672021-12-02T12:32:34ZQuantum conductance-temperature phase diagram of granular superconductor K x Fe2−y Se210.1038/s41598-018-25052-02045-2322https://doaj.org/article/8fedace8620d45d7a7b0fe7c5c9a06672018-05-01T00:00:00Zhttps://doi.org/10.1038/s41598-018-25052-0https://doaj.org/toc/2045-2322Abstract It is now well established that the microstructure of Fe-based chalcogenide K x Fe2−y Se2 consists of, at least, a minor (~15 percent), nano-sized, superconducting K s Fe2Se2 phase and a major (~85 percent) insulating antiferromagnetic K2Fe4Se5 matrix. Other intercalated A 1−x Fe2−y Se2 (A = Li, Na, Ba, Sr, Ca, Yb, Eu, ammonia, amide, pyridine, ethylenediamine etc.) manifest a similar microstructure. On subjecting each of these systems to a varying control parameter (e.g. heat treatment, concentration x,y, or pressure p), one obtains an exotic normal-state and superconducting phase diagram. With the objective of rationalizing the properties of such a diagram, we envisage a system consisting of nanosized superconducting granules which are embedded within an insulating continuum. Then, based on the standard granular superconductor model, an induced variation in size, distribution, separation and Fe-content of the superconducting granules can be expressed in terms of model parameters (e.g. tunneling conductance, g, Coulomb charging energy, E c , superconducting gap of single granule, Δ, and Josephson energy J = πΔg/2). We show, with illustration from experiments, that this granular scenario explains satisfactorily the evolution of normal-state and superconducting properties (best visualized on a $${\boldsymbol{g}}{\boldsymbol{-}}\frac{{{\boldsymbol{E}}}_{{\boldsymbol{c}}}}{{\boldsymbol{\Delta }}}{\boldsymbol{-}}{\boldsymbol{T}}$$ g−EcΔ−T phase diagram) of A x Fe2−y Se2 when any of x, y, p, or heat treatment is varied.C. C. SoaresM. ElMassalamiY. YanagisawaM. TanakaH. TakeyaY. TakanoNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 8, Iss 1, Pp 1-11 (2018)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q C. C. Soares M. ElMassalami Y. Yanagisawa M. Tanaka H. Takeya Y. Takano Quantum conductance-temperature phase diagram of granular superconductor K x Fe2−y Se2
description	Abstract It is now well established that the microstructure of Fe-based chalcogenide K x Fe2−y Se2 consists of, at least, a minor (~15 percent), nano-sized, superconducting K s Fe2Se2 phase and a major (~85 percent) insulating antiferromagnetic K2Fe4Se5 matrix. Other intercalated A 1−x Fe2−y Se2 (A = Li, Na, Ba, Sr, Ca, Yb, Eu, ammonia, amide, pyridine, ethylenediamine etc.) manifest a similar microstructure. On subjecting each of these systems to a varying control parameter (e.g. heat treatment, concentration x,y, or pressure p), one obtains an exotic normal-state and superconducting phase diagram. With the objective of rationalizing the properties of such a diagram, we envisage a system consisting of nanosized superconducting granules which are embedded within an insulating continuum. Then, based on the standard granular superconductor model, an induced variation in size, distribution, separation and Fe-content of the superconducting granules can be expressed in terms of model parameters (e.g. tunneling conductance, g, Coulomb charging energy, E c , superconducting gap of single granule, Δ, and Josephson energy J = πΔg/2). We show, with illustration from experiments, that this granular scenario explains satisfactorily the evolution of normal-state and superconducting properties (best visualized on a $${\boldsymbol{g}}{\boldsymbol{-}}\frac{{{\boldsymbol{E}}}_{{\boldsymbol{c}}}}{{\boldsymbol{\Delta }}}{\boldsymbol{-}}{\boldsymbol{T}}$$ g−EcΔ−T phase diagram) of A x Fe2−y Se2 when any of x, y, p, or heat treatment is varied.
format	article
author	C. C. Soares M. ElMassalami Y. Yanagisawa M. Tanaka H. Takeya Y. Takano
author_facet	C. C. Soares M. ElMassalami Y. Yanagisawa M. Tanaka H. Takeya Y. Takano
author_sort	C. C. Soares
title	Quantum conductance-temperature phase diagram of granular superconductor K x Fe2−y Se2
title_short	Quantum conductance-temperature phase diagram of granular superconductor K x Fe2−y Se2
title_full	Quantum conductance-temperature phase diagram of granular superconductor K x Fe2−y Se2
title_fullStr	Quantum conductance-temperature phase diagram of granular superconductor K x Fe2−y Se2
title_full_unstemmed	Quantum conductance-temperature phase diagram of granular superconductor K x Fe2−y Se2
title_sort	quantum conductance-temperature phase diagram of granular superconductor k x fe2−y se2
publisher	Nature Portfolio
publishDate	2018
url	https://doaj.org/article/8fedace8620d45d7a7b0fe7c5c9a0667
work_keys_str_mv	AT ccsoares quantumconductancetemperaturephasediagramofgranularsuperconductorkxfe2yse2 AT melmassalami quantumconductancetemperaturephasediagramofgranularsuperconductorkxfe2yse2 AT yyanagisawa quantumconductancetemperaturephasediagramofgranularsuperconductorkxfe2yse2 AT mtanaka quantumconductancetemperaturephasediagramofgranularsuperconductorkxfe2yse2 AT htakeya quantumconductancetemperaturephasediagramofgranularsuperconductorkxfe2yse2 AT ytakano quantumconductancetemperaturephasediagramofgranularsuperconductorkxfe2yse2
_version_	1718394047662391296

Quantum conductance-temperature phase diagram of granular superconductor K x Fe2−y Se2

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