Valence-bond crystal phase of the crossed-chain quantum spin model
Valence-bond crystal phase of the crossed-chain quantum spin model
Using a series expansion based on the flow-equation method we study the ground-state energy and the elementary triplet excitations of a generalized model of crossed spin-$1/2$ chains starting from the limit of decoupled quadrumers. The triplet dispersion is shown to be very sensitive to the interquadrumer frustration, exhibiting a line …