Spectral characteristics of the antiferromagnetic spin-1/2 Heisenberg model on the square lattice in a magnetic field

Abstract

We predict that spin-waves in an ordered square quantum antiferromagnet in a transverse magnetic field (h) may demonstrate three modes of spin excitations. Starting from the self-consistent rotation-invariant Green's function method, a new mean-field theory is constructed for h not equal to 0. The method preserves the translational and the axial symmetries, and provides exact fulfillment of the single-site constraint for each of the three modes. We examine the dynamical structure factors S(aa)(k,w), a= x, y, z. It is shown, that the introduction of h leads to the hybridization of two degenerate spin modes due to the appearance of a nondiagonal on a, b spin-spin Green's functions. The comparison of the theory with the exact diagonalization study and with results on inelastic neutron scattering experiments is discussed at T = 0. We discuss also the correspondence of the theory to the existing theories, which allow only two spin excitations modes for the total S(k,w).

arXiv comment13 pages, 3 figures

References in corpus (17)

• Frustrated two dimensional quantum magnets
• Instability of antiferromagnetic magnons in strong fields
• The antiferromagnetic spin-1/2 Heisenberg model on the square lattice in a magnetic field
• Instability of Magnons in Two-dimensional Antiferromagnet at High Magnetic Fields
• 2D XY Behavior observed in quasi-2D quantum Heisenberg antiferromagnets
• Field-induced decay dynamics in square-lattice antiferromagnet
• Quantum effects in a weakly-frustrated S=1/2 two-dimensional Heisenberg antiferromagnet in an applied magnetic field
• Field induced spontaneous quasiparticle decay and renormalization of quasiparticle dispersion in a quantum antiferromagnet
• Two-dimensional quantum-spin-1/2 XXZ magnet in zero magnetic field: global thermodynamics from renormalization group theory
• Frustrated spin-$\frac{1}{2}$ Heisenberg magnet on a square-lattice bilayer: High-order study of the quantum critical behavior of the $J_1$--$J_2$--$J_1^{\perp }$ model
• Two-dimensional Heisenberg antiferromagnet in a transverse field
• Dynamical structure factor of quasi-2D antiferromagnet in high fields
• Thermodynamics of the pyrochlore Heisenberg ferromagnet with arbitrary spin $S$
• The Spin-Half {\it XXZ} Antiferromagnet on the Square Lattice Revisited: A High-Order Coupled Cluster Treatment
• Thermodynamic properties of the 2D frustrated Heisenberg model for the entire $J_1-J_2$ circle
• Spin Hartree-Fock approach to quantum Heisenberg antiferromagnets in low dimensions
• Stability of the d-wave pairing with respect to the intersite Coulomb repulsion in cuprate superconductors

Cited by in corpus (2)

• Spin-half Heisenberg antiferromagnet on a symmetric sawtooth chain: Rotation-invariant Green's functions and high-temperature series
• Quantum Heisenberg model on a sawtooth-chain lattice: Rotation-invariant Green's function method