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Controlling T c through Band Structure and Correlation Engineering in Collapsed and Uncollapsed Phases of Iron Arsenides

Research output: Contribution to journalArticle

Original languageEnglish
Pages (from-to)1-5
JournalPhysical Review Letters
Issue number23
Early online date11 Jun 2020
Publication statusPublished - 12 Jun 2020


  • Controlling Tc through Band_ACHARYA_Acc21Apr2020Epub11Jun2020_GREEN VoR

    Controlling_Tc_through_Band_ACHARYA_Acc21Apr2020Epub11Jun2020_GREEN_VoR.pdf, 919 KB, application/pdf


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    As of 2018, PRL is part of the Sponsoring Consortium for Open Access Publishing in Particle Physics. All high-energy physics articles published in PRL since January 1, 2018, and that are posted on arXiv under one of the four "hep" primary designations, are made open access under a Creative Commons Attribution license under the auspices of SCOAP3.

King's Authors


Recent observations of selective emergence (suppression) of superconductivity in the uncollapsed
(collapsed) tetragonal phase of LaFe2 As2 has rekindled interest in understanding what features of the band
structure control the superconducting T c . We show that the proximity of the narrow Fe-dxy state to the
Fermi energy emerges as the primary factor. In the uncollapsed phase this state is at the Fermi energy, and is
most strongly correlated and a source of enhanced scattering in both single and two particle channels. The
resulting intense and broad low energy spin fluctuations suppress magnetic ordering and simultaneously
provide glue for Cooper pair formation. In the collapsed tetragonal phase, the dxy state is driven far below
the Fermi energy, which suppresses the low-energy scattering and blocks superconductivity. A similar
source of broad spin excitation appears in uncollapsed and collapsed phases of CaFe2As2 . This suggests
controlling coherence provides a way to engineer T c in unconventional superconductors primarily
mediated through spin fluctuations.

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