Figure 4
From: Topological incommensurate magnetization plateaus in quasi-periodic quantum spin chains
Spin-flip excitation spectrum for quasi-periodic spin-1 Heisenberg model.
(a) Magnetization curves for AFM spin-1 Heisenberg model with 
, λ = 0.3 and L = 100 under PBC. The blue dotted lines are guidelines for the incommensurate plateaus. (b) Spin-flip excitation spectrum 
with respect to phase δ for spin-1 AFM Heisenberg chains with 
under OBC. The five large excitation gaps correspond to magnetization plateaus Pα, P2α, “Haldane” 0-plateau, P−2α and P−α from bottom to top. (c) and (d) Distributions 
of in-gap spin-flip excitation modes for plateaus P−α and P−2α, respectively. For each in-gap mode, Sz = mlL.
