Investigation of spectrum and bound states of the energy operator of two-magnon system in a non-Heisenberg ferromagnetic with spin S=2 and nearest-neighbor interactions

Анотація

We consider two-magnon systems in an ν-dimensional isotropic Non-Heisenberg ferromagnet with spin value S=2 and nearest-neighbor interactions. Spectrum and bound states (BS) of the system for all values of full quasi-momentum Λ, and for arbitrary value of lattice dimensionality ν, and for all values of Hamiltonian parameters are investigated. We show that (i) for arbitrary ν≥2 and for full quasi-momentum in the form Λ=(Λ₁;Λ₂;…;Λ_ν)=(Λ₀;Λ₀;…;Λ₀)the change of energy spectrum of the system is similar to that observed in the case of ν=1. In this case the operator Ĥ₂ with J+5J₁-83J₂+773J₃≠0 has only one additional BS. (ii) The energy z of this additional BS is degenerate ν-1 times. (iii) If Λ≠(Λ₀;Λ₀;…;Λ₀), we show the existence no more 2ν+1 BS in the system in ν-dimensional lattice.