Crystal structure, lattice dynamics and superexchange in MAgF3 1D antiferromagnets (M = K, Rb, Cs) and Rb3Ag2F7 Ruddlesden-Popper phase

Autor:	Koteras, Kacper, Gawraczynski, Jakub, Tavcar, Gasper, Mazej, Zoran, Grochala, Wojciech
Rok vydání:	2021
Předmět:	Condensed Matter - Materials Science Condensed Matter - Strongly Correlated Electrons
Druh dokumentu:	Working Paper
DOI:	10.1039/D1CE01545A
Popis:	With the use of lattice dynamics calculation within hybrid HSE06 framework we were able to understand vibrational spectra of MAgF3 M = K, Rb, Cs compounds. Comparative theoretical study uncovered lack of monotonicity in calculated optical phonons associated with Ag F stretching modes which can be explained through an interplay of Lewis acidity of MI cation and its size. We confirm the tetragonal unit cells of MAgF3 M=Rb, Cs at room temperature. We also theoretically predict an orthorhombic RbAgF3 polymorph as a ground state at low temperature. However, we were not able to detect it by the means of low temperature PXRD at 80 K nor low temperature Raman at 154 K due to a number of constraints. We also describe a novel Ruddlesden Popper phase of Rb3Ag2F7 which can be regarded as quasi 0D system, where superexchange coupling constant between the nearest AgII centres reaches an impressive value of minus 240.2 meV. Comment: 13 pages, 12 figures, 3 tables, and supplementary information
Databáze:	arXiv
Externí odkaz:	http://arxiv.org/abs/2111.08539 Zobrazit plný text záznamu View this record from Arxiv