Magnon–lattice dynamics in a Heisenberg–Morse model with spin–lattice interaction

Abstract

We investigate the dynamics of a single magnon excitation in a quantum Heisenberg model under the effect of lattice vibrations. The Heisenberg spins are set on a nonlinear Morse chain, with the coupling depending on their distance. We solve the time evolution numerically and discuss the magnon velocity’s dependence on the spin–lattice coupling. Our results show that the lattice deformation embodies a finite fraction of the spin wave function in the robust spin–lattice coupling regime, generating a mobile magnon–lattice excitation. We also analyze the lattice deformation and magnon wave functions separately. Our results indicate both spatial profiles display solitonic features.