Antiferromagnetic integer-spin chains in a staggered magnetic field: Approaching the thermodynamic limit through the infinite-size density-matrix renormalization group

We investigate the behavior of antiferromagnetic integer-spin chains in a staggered magnetic field, by means of the density-matrix renormalization group, carefully addressing the role of finite-size effects within the Haldane phase at small fields. In the case of spin S = 2, we determine the dependence of the ground-state energy and magnetization on the external field. in the thermodynamic limit. and show how the peculiar finite-size behavior can be connected with the crossover in the ground state from a spin liquid to a polarized Neel state.