Exact diagonalization study of the antiferromagnetic spin-12Heisenberg model on the square lattice in a magnetic field

2008/12/31 by Andreas Lüscher, Andreas Luscher, Andreas Laeuchli +1 · 4 citations
Physics and Astronomy · #Advanced Condensed Matter Physics #Antiferromagnetism #Brillouin zone #Condensed matter physics #Ferromagnetism #Inelastic neutron scattering #Magnetic properties of thin films #Magnon #Neutron scattering #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Scattering #Spin (aerodynamics) #Spin wave #cond-mat.str-el

paper · pdf · doi:10.1103/physrevb.79.195102

published as Phys. Rev. B 79, 195102 (2009) · 15 pages, 15 figures

arxiv created 2009/03/16 · openalex publication_date 2009/05/05 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

We study the field dependence of the antiferromagnetic spin-(1)/(2) Heisenberg model on the square lattice by means of exact diagonalizations. In the first part, we calculate the spin-wave velocity c, the spin stiffness \ensuremathρ_s, and the magnetic susceptibility \ensuremathχ_\ensuremath⊥, and thus determine the microscopic parameters of the low-energy long-wavelength description. In the second part, we present a comprehensive study of dynamical spin-correlation functions for magnetic fields ranging from zero up to saturation. We find that, at low fields, magnons are well defined in the whole Brillouin zone but the dispersion is substantially modified by quantum fluctuations compared to the classical spectrum. At higher fields, decay channels open and magnons become unstable with respect to multimagnon scattering. Our results directly apply to inelastic neutron-scattering experiments.

Citations

• The two dimensional antiferromagnetic Heisenberg model in the presence of an external field
• Two-dimensional quantum Heisenberg antiferromagnet: Effective-Hamiltonian approach to the thermodynamics
• Numerical evidence for unstable magnons at high fields in the Heisenberg antiferromagnet on the square lattice
• Magnetic Order and Disorder in the Frustrated Quantum Heisenberg Antiferromagnet in Two Dimensions
• Spin Waves and Electronic Interactions inLa2CuO4
• Quantum Heisenberg antiferromagnets in a uniform magnetic field: Nonanalytic magnetic field dependence of the magnon spectrum
• Magnetic order in theS=1∕2two-dimensional molecular antiferromagnet copper pyrazine perchlorateCu(Pz)2(ClO4)2
• Instability of Antiferromagnetic Magnons in Strong Fields

Cited by

• Field-induced quasi-bound state within the two-magnon continuum of a square-lattice Heisenberg antiferromagnet
• Antiferromagnetic magnons and local anisotropy: dynamical mean-field study
• Antiferromagnetic films in weak magnetic and staggered fields
• Fermionic two-loop functional renormalization group for correlated fermions: Method and application to the attractive Hubbard model