Inspired by the recent experiments on Y2-xCaxBaNiO5, we discuss the dispersion relation of the S=1/2 particles in the S=1 Heisenberg and valence bond solid model in the limit of small hopping amplitudes. The effective S=1/2 edge spins mix with the spin of the impurity resulting in one fourfold and two twofold degenerate bands. We briefly discuss the interaction between the S=1/2 particles arising from the background.
ASJC Scopus subject areas
- Condensed Matter Physics