Dresden 2017 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 24: Low-Dimensional Systems: 1D - Theory
TT 24.5: Vortrag
Dienstag, 21. März 2017, 10:30–10:45, HSZ 204
Thermal Intra-Band Magnon Scattering in the Haldane Spin-One Chain — •Jonas Becker1, Thomas Köhler2, Alexander C. Tiegel2, Salvatore R. Manmana2, Andreas Honecker3, and Stefan Wessel1 — 1Institute for Theoretical Solid State Physics, RWTH Aachen University, 52056 Aachen, Germany — 2Institut für Theoretische Physik, Georg-August-Universität Göttingen, 37077 Göttingen, Germany — 3Laboratoire de Physique Théorique et Modélisation, CNRS UMR 8089, Université de Cergy-Pontoise, F-95302 Cergy-Pontoise Cedex, France
We present results from a thorough evaluation of the dynamical spin structure factor of the Haldane chain at finite temperatures, based on a combination of exact numerical diagonalization, finite-temperature density-matrix renormalization group calculations and quantum Monte Carlo simulations. Simulations performed on finite open chains exhibit a sub-gap band in the thermal spin spectral function, indicative of the localized edge-modes in the Haldane chain's ground state. Furthermore, we observe the thermal activation of a distinct low-energy contribution to the spin spectral function with an enhanced spectral weight at low momenta that results from intra-band magnon scattering due to the thermal population of the single-magnon mode. These findings are discussed with respect to previous results on the spin spectral function and possible future studies on Haldane spin chain compounds based on inelastic neutron scattering experiments.