Dynamic structure factor of the spin- 12 XXZ chain in a transverse field

Publikation: Beitrag in FachzeitschriftForschungsartikelBeigetragenBegutachtung

Beitragende

  • Benedikt Bruognolo - , Ludwig-Maximilians-Universität München (LMU) (Autor:in)
  • Andreas Weichselbaum - , Ludwig-Maximilians-Universität München (LMU) (Autor:in)
  • Jan Von Delft - , Ludwig-Maximilians-Universität München (LMU) (Autor:in)
  • Markus Garst - , Professur für Theoretische Festkörperphysik, Universität zu Köln, Technische Universität Dresden (Autor:in)

Abstract

The spin-12 XXZ chain with easy-plane anisotropy in a transverse field describes well the thermodynamic properties of the material Cs2CoCl4 in a wide range of temperatures and fields including the region close to the spin-flop Ising quantum phase transition. For a comparison with prospective inelastic neutron scattering experiments on this compound, we present results of an extensive numerical study of its dynamic structure factor Sαβ(k,ω) using matrix-product-state (MPS) techniques. Close to criticality, the dynamic part of the correlator Sxx longitudinal to the applied field is incoherent and possesses a small total weight as the ground state is already close to saturation. The transverse correlator Szz, on the other hand, is dominated by a coherent single-particle excitation with additional spectral weight at higher energies that we tentatively attribute to a repulsively bound pair of particles. With increasing temperature, the latter quickly fades and spectral weight instead accumulates close to zero wave vector just above the single-particle energy. On a technical level, we compare the numerical efficiency of real-time evolution to an MPS-based Chebyshev expansion in the present context, finding that both methods yield results of similar quality at comparable numerical costs.

Details

OriginalspracheEnglisch
Aufsatznummer085136
FachzeitschriftPhysical Review B
Jahrgang94
Ausgabenummer8
PublikationsstatusVeröffentlicht - 22 Aug. 2016
Peer-Review-StatusJa