Spin Excitation and Phonon Effect for Frustrated Spin-Peierls Model

Abstract

We study spin excitation for a spin-Peierls chain with nearest-neighbour and next-nearest-neighbour Heisenberg spin exchange interactions. Lattice degree of freedom is introduced as a gapped and dispersionless (Einstein) phonon, and its effect is renormalized to the spin exchange interactions. We apply a dynamical density matrix renormalization group method to calculate the dynamical spin structure factor of the renormalized spin model. By using this method, we can obtain differences in spin excitation between the spin-liquid phase and the dimer phase.