Cupratelike electronic and magnetic properties of layered transition-metal difluorides from first-principles calculations
Clark Miller, Antía S. Botana
Abstract
The electronic and magnetic properties of two isoelectronic layered transition-metal fluorides (${\mathrm{AgF}}_{2}$ and ${\mathrm{CuF}}_{2}$) are considered in the context of high-temperature superconducting cuprates. The properties of ${\mathrm{AgF}}_{2}$ are found to be cupratelike comprising a layered spin-$\frac{1}{2}$ system with strong $p\ensuremath{-}d$ hybridization, and a large two-dimensional antiferromagnetic superexchange interaction, comparable to cuprates. Contrary to its Ag-counterpart, ${\mathrm{CuF}}_{2}$ shows a small degree of $p\ensuremath{-}d$ hybridization and a superexchange interaction one order of magnitude smaller than in cuprates. Within the Zaanen-Sawatzky-Allen model ${\mathrm{AgF}}_{2}$ and ${\mathrm{CuF}}_{2}$ could be classified as a charge-transfer and Mott-Hubbard insulator, respectively. As a consequence, this work further demonstrates the promise ${\mathrm{AgF}}_{2}$ holds as a parent compound to a new class of Ag-based superconducting materials, whereas ${\mathrm{CuF}}_{2}$ is not promising as a cuprate analog.