Center of New Technologies, University of Warsaw, 02089 Warsaw, Poland.
Faculty of Chemistry, University of Warsaw, 02093 Warsaw, Poland.
Proc Natl Acad Sci U S A. 2019 Jan 29;116(5):1495-1500. doi: 10.1073/pnas.1812857116. Epub 2019 Jan 16.
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.
高 Tc 超导铜酸盐母体化合物是一种独特的莫特绝缘体，由自旋为[Formula: see text]的离子层组成，形成一个正方形晶格，具有记录最高的面内反铁磁耦合。具有类似特性的化合物长期以来一直被人们寻找，但都没有成功。在这里，我们使用实验和理论工具的组合表明，商业[Formula: see text]是一种极好的铜酸盐类似物，其电子参数与[Formula: see text]非常相似，但平面的弯曲更大。双磁振子拉曼散射和非弹性中子散射表明超交换常数达到典型铜酸盐的 70%。我们认为，减少或消除[Formula: see text]平面弯曲的结构可能具有与铜酸盐相匹配或超过的反铁磁耦合。
