Title Fe-vacancy order and superconductivity in tetragonal $\beta-Fe_{1-x}Se$ Fe-vacancy order and superconductivity in tetragonal $\beta-Fe_{1-x}Se$ Author Chen, Ta-Kun Chang, Chung-Chieh Chang, Hsian-Hong Van Dyck, Dirk et al. Faculty/Department Faculty of Sciences. Physics Publication type article Publication 2014 Washington, D.C. , 2014 Subject Engineering sciences. Technology Source (journal) Proceedings of the National Academy of Sciences of the United States of America. - Washington, D.C. Volume/pages 111(2014) :1 , p. 63-68 ISSN 0027-8424 1091-6490 ISI 000329350700039 Carrier E Target language English (eng) Full text (Publishers DOI) Affiliation University of Antwerp Abstract Several superconducting transition temperatures in the range of 30-46 K were reported in the recently discovered intercalated FeSe system (A(1-x)Fe(2-y)Se(2), A = K, Rb, Cs, Tl). Although the superconducting phases were not yet conclusively decided, more than one magnetic phase with particular orders of iron vacancy and/or potassium vacancy were identified, and some were argued to be the parent phase. Here we show the discovery of the presence and ordering of iron vacancy in nonintercalated FeSe (PbO-type tetragonal beta-Fe1-xSe). Three types of iron-vacancy order were found through analytical electron microscopy, and one was identified to be non-superconducting and magnetic at low temperature. This discovery suggests that the rich-phases found in A(1-x)Fe(2-y)Se(2) are not exclusive in Fe-Se and related superconductors. In addition, the magnetic beta-Fe1-xSe phases with particular iron-vacancy orders are more likely to be the parent phase of the FeSe superconducting system instead of the previously assigned beta-Fe1+delta Te. E-info https://repository.uantwerpen.be/docman/iruaauth/76dd81/28a7054.pdf http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000329350700039&DestLinkType=RelatedRecords&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000329350700039&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000329350700039&DestLinkType=CitingArticles&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 Handle