The superconducting transition temperatures of Fe1+xSe 1y, Fe1+xSe1yTey and (K/Rb/Cs) zFe2xSe2

Document Type

Article

Publication Date

4-4-2012

Abstract

In a recent contribution to this journal, it was shown that the transition temperatures of optimal high-TC compounds obey the algebraic relation TC0 = k-1B β/ℓζ, where ℓ is related to the mean spacing between interacting charges in the layers, is the distance between interacting electronic layers, β is a universal constant and kB is Boltzmanns constant. The equation was derived assuming pairing based on interlayer Coulomb interactions between physically separated charges. This theory was initially validated for 31 compounds from five different high-TC families (within an accuracy of ±1.37K). Herein we report the addition of Fe1+xSe1y and Fe 1+xSe1yTey (both optimized under pressure) and AzFe2xSe2 (for A=K, Rb or Cs) to the growing list of Coulomb-mediated superconducting compounds in which TC0 is determined by the above equation. Doping in these materials is accomplished through the introduction of excess Fe and/or Se deficiency, or a combination of alkali metal and Fe vacancies. Consequently, a very small number of vacancies or interstitials can induce a superconducting state with a substantial transition temperature. The confirmation of the above equation for these Se-based Fe chalcogenides increases to six the number of superconducting families for which the transition temperature can be accurately predicted. © 2012 IOP Publishing Ltd.

Identifier

84858678869 (Scopus)

Publication Title

Journal of Physics Condensed Matter

External Full Text Location

https://doi.org/10.1088/0953-8984/24/13/135701

e-ISSN

1361648X

ISSN

09538984

PubMed ID

22370161

Issue

13

Volume

24

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