Dresden 2017 – scientific programme
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MA: Fachverband Magnetismus
MA 17: PhD Symposium: Quantum Magnets: Frustration and Topology in Experiment and Theory (jointly with Young DPG (jDPG)
MA 17.8: Talk
Tuesday, March 21, 2017, 14:45–15:00, HSZ 04
Dimensional reduction due to geometric frustration – a case study — •Ulrich Tutsch1, Burkhard Schmidt2, Lars Postulka1, Bernd Wolf1, Natalija van Well1, Franz Ritter1, Cornelius Krellner1, Wolf Assmus1, and Michael Lang1 — 1Physikalisches Institut, Goethe-Universität Frankfurt, SFB/TR 49, 60438 Frankfurt (M), Germany — 2Max-Planck-Institut für Chemische Physik fester Stoffe, 01187 Dresden, Germany
Theoretical studies suggest that the frustrating zigzag bonds between the spin chains in triangular-lattice Heisenberg antiferromagnets gives rise to one-dimensional behaviour as long as J′/J ≤ 0.7. Cs2CuCl4−xBrx (0≤ x≤4) represents a good realization of such a system where the ratio J′/J of the in-plane spin-spin exchange coupling constants varies from 0.30 (x = 0) to 0.63 (x = 2), thus providing a well-suited model system for testing the frustration-induced dimensional-reduction scenario.
Here, we present specific heat data below 1 K for the compounds Cs2CuCl2Br2 and Cs2CuCl3Br, which, due to site-selective substitution, show a well-ordered halide sublattice. The results for zero magnetic field for these systems as well as for the border compounds x = 0 and x = 4 can be well described by the antiferromagnetic Heisenberg chain model, fully consistent with frustration-induced one-dimensional behaviour.