Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 5: Correlated Electrons: Spin Systems and Itinerant Magnets – Frustrated Magnets 1 (jointly with MA)

TT 5.2: Talk

Monday, March 16, 2015, 09:45–10:00, H 0110

Finite-temperature dynamics of a highly frustrated quantum spin ladder — •Andreas Honecker¹ and Bruce Normand² — ¹LPTM, Université de Cergy-Pontoise, France — ²Renmin University of China, Beijing

Highly-frustrated magnets are characterized by a (nearly) flat one-triplet excitation band at zero temperature. Little is known from theoretical studies about the temperature-dependence of this single-particle dispersion and less still concerning multi-particle dynamics at finite temperature. Experimentally, inelastic neutron scattering studies of low-dimensional frustrated systems such as SrCu₂(BO₃)₂ require an interpretation of the thermal evolution of scattering intensities. We investigate these issues using the example of a highly frustrated spin-1/2 ladder. We find that single- and many-particle excitations persist as sharp spectral features in the dynamic structure factor to surprisingly high and even infinite temperatures. In addition, in a relevant parameter regime low-lying excitations give rise to an anomalously rapid transfer of spectral weight out of the single-particle band to a wide range of energies.