Ground-state properties and quantum entanglement in rung-dimerized spin-1/2 antiferromagnetic ladder

The ground-state properties and quantum entanglement of the two-leg rung-dimerized spin-1/2 Heisenberg antiferromagnetic ladders are investigated based on the Green' function combined with the Bond mean-field theory. Numerical results show that the ground-state energies do not change with the rung dimerization, and the ground-state gaps are almost proportionate to the rung dimerization coefficient delta and coupling strength alpha. Magnetization curves and entanglement measurements demonstrate that there are five magnetic phases, which are identified in the h-delta phase diagram. Entanglement measurements in different phases exhibit distinct behaviors, implying the fundamental differences of the five magnetic phases. (c) 2013 Elsevier B.V. All rights reserved.