Magnetic properties and quantum entanglement on decorated zigzag ladder

Magnetic properties and quantum entanglement of Heisenberg model with two-, three- and four-site exchange interactions on zigzag ladder are studied. Magnetic properties and concurrence (measure of quantum entanglement) are analyzed by means of variational mean-field-like treatment based on the Gibbs-Bogoliubov inequality. The magnetization plateau and second-order phase transition are obtained. A comparison of the entanglement and magnetic characteristics for the zigzag ladder is made. Our calculations show that in the antiferromagnetic region the behavior of the concurrence coincides with that of the magnetization.