Infrared spectra of the low-dimensional quantum magnet SrCu2(BO3)2 : Measurements and ab initio calculations

C. C. Homes,1,2,* S. V. Dordevic,1,3 A. Gozar,1 G. Blumberg,4,5 T. Room,5 D. Huvonen,5 U. Nagel,5 A. D. LaForge,6 D. N. Basov,6 and H. Kageyama7 1Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, USA 2Laboratoire Photons et Matiere, UPR-5 CNRS, ESPCI, 10 Rue Vauquelin, 75231 Paris Cedex 5, France 3Department of Physics, The University of Akron, Akron, Ohio 44325, USA 4Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA 5National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618 Tallinn, Estonia 6Department of Physics, University of California-San Diego, San Diego, La Jolla, California 92093, USA 7Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan Received 16 June 2008; revised manuscript received 28 November 2008; published 4 March 2009