title: Correlated decay of triplet excitations in the Shastry-Sutherland compound SrCu2(BO3)2.
abstract: The temperature dependence of the gapped triplet excitations (triplons) in the 2D Shastry-Sutherland quantum magnet SrCu(2)(BO(3))(2) is studied by means of inelastic neutron scattering. The excitation amplitude rapidly decreases as a function of temperature, while the integrated spectral weight can be explained by an isolated dimer model up to 10 K. Analyzing this anomalous spectral line shape in terms of damped harmonic oscillators shows that the observed damping is due to a two-component process: one component remains sharp and resolution limited while the second broadens. We explain the underlying mechanism through a simple yet quantitatively accurate model of correlated decay of triplons: an excited triplon is long lived if no thermally populated triplons are nearby but decays quickly if there are. The phenomenon is a direct consequence of frustration induced triplon localization in the Shastry-Sutherland lattice.
authors.affiliation: Department of Mathematics, Statistics and Physics, College of Arts and Science, Qatar University, P.O. Box 2713, Doha, Qatar and Laboratory for Quantum Magnetism, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland and Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
authors.forename: M E
authors.initials: ME
authors.lastname: Zayed
authors.affiliation: Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland and DPMC-MaNEP, University of Geneva, CH-1211 Geneva, Switzerland and London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom.
authors.forename: Ch
authors.initials: Ch
authors.lastname: Rüegg
authors.affiliation: Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
authors.forename: Th
authors.initials: T
authors.lastname: Strässle
authors.affiliation: Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
authors.forename: U
authors.initials: U
authors.lastname: Stuhr
authors.affiliation: Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
authors.forename: B
authors.initials: B
authors.lastname: Roessli
authors.affiliation: Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Ay
authors.affiliation: Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland and Laboratory for Neutron and Synchrotron Spectroscopy, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland and Laboratory for Solid State Physics, ETH Zurich, CH-8093 Zurich, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Mesot
authors.affiliation: Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM-2), D-85747 Garching, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Link
authors.affiliation: Laboratory for Developments and Methods, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
authors.forename: E
authors.initials: E
authors.lastname: Pomjakushina
authors.affiliation: Laboratory for Developments and Methods, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Stingaciu
authors.affiliation: Laboratory for Developments and Methods, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
authors.forename: K
authors.initials: K
authors.lastname: Conder
authors.affiliation: Laboratory for Quantum Magnetism, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
authors.forename: H M
authors.initials: HM
authors.lastname: Rønnow