title: Magnetic Behavior of Volborthite Cu_{3}V_{2}O_{7}(OH)_{2}·2H_{2}O Determined by Coupled Trimers Rather than Frustrated Chains.
abstract: Motivated by recent experiments on volborthite single crystals showing a wide 1/3-magnetization plateau, we perform microscopic modeling by means of density functional theory (DFT) with the single-crystal structural data as a starting point. Using DFT+U, we find four leading magnetic exchanges: antiferromagnetic J and J_{2}, as well as ferromagnetic J^{'} and J_{1}. Simulations of the derived spin Hamiltonian show good agreement with the experimental low-field magnetic susceptibility and high-field magnetization data. The 1/3-plateau phase pertains to polarized magnetic trimers formed by strong J bonds. An effective J→∞ model shows a tendency towards condensation of magnon bound states preceding the plateau phase.
authors.affiliation: Institut für Festkörperphysik, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria.
authors.forename: O
authors.initials: O
authors.lastname: Janson
authors.affiliation: Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Furukawa
authors.affiliation: Condensed Matter Theory Laboratory, RIKEN, Wako, Saitama 351-0198, Japan.|RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Momoi
authors.affiliation: Laboratoire de Physique Théorique de la Matière Condensée, Université P. & M. Curie, 75252 Paris, France.
authors.forename: P
authors.initials: P
authors.lastname: Sindzingre
authors.affiliation: Institut für Theoretische Physik, Universität Magdeburg, D-39016 Magdeburg, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Richter
authors.affiliation: Institut für Festkörperphysik, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria.
authors.forename: K
authors.initials: K
authors.lastname: Held