Charge ordering mechanism in silver difluoride

2021/08/21 by Mariana Derzsi, Kamil Tokár, Przemysław Piekarz +1 · 7 citations
Chemistry · Physics and Astronomy · #Advanced Chemical Physics Studies #Charge (physics) #Charge ordering #Chemistry #Condensed matter physics #Electron #Fermi surface #Hubbard model #Inorganic Fluorides and Related Compounds #Instability #Lattice (music) #Materials science #Metal #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Superconductivity #cond-mat.str-el

paper · pdf · doi:10.1103/physrevb.105.l081113

published in Physical review. B./Physical review. B 105(8) (American Physical Society) · 6 pager, 4 figures

arxiv created 2021/08/21 · openalex publication_date 2022/02/24 · openalex created_date 2022/02/25 · arxiv updated 2022/02/28 · openalex updated_date 2026/07/22

Abstract

Using density functional theory, a competition between the Mott-Hubbard and intervalence charge transfer mechanism of electron localization is revealed in AgF₂, an important silver analog of oxocuprates. We show that at reduced temperature and electron correlations AgF₂ becomes metallic and dynamically unstable with respect to soft phonon modes that promote charge ordering. The charge density wave (CDW) instability is closely related to the Kohn anomaly and Fermi surface nesting. The long advocated KBrF₄-type CDW Ag^1+/3+F₂ structure and its facile transformation to the ground state Ag²⁺F₂ phase is explained. Our results point to an intimate interplay between lattice, charge, and spin degrees of freedom in this seemingly simplistic binary metal fluoride.

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