Finite-temperature dynamical structure factor of the Heisenberg-Ising chain

Journal article

We consider the spin-1/2 Heisenberg XXZ chain in the regime of large Ising-type anisotropy Δ. By a combination of duality and Jordan-Wigner transformations we derive a mapping to weakly interacting spinless fermions, which represent domain walls between the two degenerate ground states. We develop a perturbative expansion in 1/Δ for the transverse dynamical spin structure factor at finite temperatures and in an applied transverse magnetic field. We present a unified description for both the low-energy temperature-activated response and the temperature evolution of the T=0 two-spinon continuum. We find that the two-spinon continuum narrows in energy with increasing temperature. At the same time spectral weight is transferred from the two-spinon continuum to the low-energy intraband scattering continuum, which is strongly peaked around the position of the (single) spinon dispersion ("Villain mode"). © 2009 The American Physical Society.

Authors: James, A; Goetze, W; Essler, F

• Publication status: Published
• Journal: Physical Review B
• Volume: 79
• Issue: 21
• Publication date: 2009-06-01
• DOI: 10.1103/PhysRevB.79.214408
• EISSN: 1550-235X
• ISSN: 1098-0121
• Language: English
• Keywords: magnetic domain walls; Heisenberg model; magnetic structure; magnetic anisotropy; fermion systems; Ising model; ground states; perturbation theory