期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2019
卷号：116
期号：5
页码：1495-1500
DOI：10.1073/pnas.1812857116
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The parent compound of high- T c superconducting cuprates is a unique Mott insulator consisting of layers of spin- 1 2 ions forming a square lattice and with a record high in-plane antiferromagnetic coupling. Compounds with similar characteristics have long been searched for without success. Here, we use a combination of experimental and theoretical tools to show that commercial A g F 2 is an excellent cuprate analog with remarkably similar electronic parameters to L a 2 C u O 4 but larger buckling of planes. Two-magnon Raman scattering and inelastic neutron scattering reveal a superexchange constant reaching 70% of that of a typical cuprate. We argue that structures that reduce or eliminate the buckling of the A g F 2 planes could have an antiferromagnetic coupling that matches or surpasses the cuprates.
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