title: Magnetic Excitations and Electronic Interactions in Sr_{2}CuTeO_{6}: A Spin-1/2 Square Lattice Heisenberg Antiferromagnet.
abstract: Sr_{2}CuTeO_{6} presents an opportunity for exploring low-dimensional magnetism on a square lattice of S=1/2  Cu^{2+} ions. We employ ab initio multireference configuration interaction calculations to unravel the Cu^{2+} electronic structure and to evaluate exchange interactions in Sr_{2}CuTeO_{6}. The latter results are validated by inelastic neutron scattering using linear spin-wave theory and series-expansion corrections for quantum effects to extract true coupling parameters. Using this methodology, which is quite general, we demonstrate that Sr_{2}CuTeO_{6} is an almost ideal realization of a nearest-neighbor Heisenberg antiferromagnet but with relatively weak coupling of 7.18(5) meV.
authors.affiliation: Laboratory for Quantum Magnetism, Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
authors.forename: P
authors.initials: P
authors.lastname: Babkevich
authors.affiliation: Chair of Computational Condensed Matter Physics, Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
authors.forename: Vamshi M
authors.initials: VM
authors.lastname: Katukuri
authors.affiliation: Institut Laue-Langevin, CS 20156, F-38042 Grenoble Cedex 9, France.
authors.forename: B
authors.initials: B
authors.lastname: Fåk
authors.affiliation: Institut Laue-Langevin, CS 20156, F-38042 Grenoble Cedex 9, France.
authors.forename: S
authors.initials: S
authors.lastname: Rols
authors.affiliation: Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, CH-5232 Villigen, Switzerland.
authors.forename: T
authors.initials: T
authors.lastname: Fennell
authors.affiliation: Department of Physics, Faculty of Science, University of Zagreb, Bijenička cesta 32, HR-10000 Zagreb, Croatia.
authors.forename: D
authors.initials: D
authors.lastname: Pajić
authors.affiliation: Department of Physics, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: T
authors.initials: T
authors.lastname: Pardini
authors.affiliation: Department of Physics, University of California, Davis, California 95616, USA.
authors.forename: R R P
authors.initials: RR
authors.lastname: Singh
authors.affiliation: Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, Université Paris-Est, 5 boulevard Descartes, 77454 Marne-la-Vallée, France.
authors.forename: A
authors.initials: A
authors.lastname: Mitrushchenkov
authors.affiliation: Chair of Computational Condensed Matter Physics, Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
authors.forename: O V
authors.initials: OV
authors.lastname: Yazyev
authors.affiliation: Laboratory for Quantum Magnetism, Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
authors.forename: H M
authors.initials: HM
authors.lastname: Rønnow