Superconductivity in undoped BaFe 2 As 2 by tetrahedral geometry design

Fe-based superconductors exhibit a diverse interplay between charge, orbital, and magnetic ordering. Variations in atomic geometry affect electron hopping between Fe atoms and the Fermi surface topology, influencing magnetic frustration and the pairing strength through changes of orbital overlap and...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2020-09, Vol.117 (35), p.21170-21174
Main Authors: Kang, Jong-Hoon, Kim, Jong-Woo, Ryan, Philip J, Xie, Lin, Guo, Lu, Sundahl, Chris, Schad, Jonathon, Campbell, Neil, Collantes, Yesusa G, Hellstrom, Eric E, Rzchowski, Mark S, Eom, Chang-Beom
Format: Article
Language:English
Subjects:
atomic geometry
CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
epitaxial heterostructure
low dimension
superconductivity
superlattice
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Summary:Fe-based superconductors exhibit a diverse interplay between charge, orbital, and magnetic ordering. Variations in atomic geometry affect electron hopping between Fe atoms and the Fermi surface topology, influencing magnetic frustration and the pairing strength through changes of orbital overlap and occupancies. Here, we experimentally demonstrate a systematic approach to realize superconductivity without chemical doping in BaFe As , employing geometric design within an epitaxial heterostructure. We control both tetragonality and orthorhombicity in BaFe As through superlattice engineering, which we experimentally find to induce superconductivity when the As-Fe-As bond angle approaches that in a regular tetrahedron. This approach to superlattice design could lead to insights into low-dimensional superconductivity in Fe-based superconductors.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.2001123117