Silver route to cuprate analogs.

Gawraczyński, Jakub; Kurzydłowski, Dominik; Ewings, Russell A; Bandaru, Subrahmanyam; Gadomski, Wojciech; Mazej, Zoran; Ruani, Giampiero; Bergenti, Ilaria et al. · Proc Natl Acad Sci U S A · 2019

basic_science · Level V

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Abstract

The parent compound of high-[Formula: see text] superconducting cuprates is a unique Mott insulator consisting of layers of spin-[Formula: see text] 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 [Formula: see text] is an excellent cuprate analog with remarkably similar electronic parameters to [Formula: see text] 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 [Formula: see text] planes could have an antiferromagnetic coupling that matches or surpasses the cuprates.