Combined analytical and numerical approach to study magnetization plateaux in doped quasi-one-dimensional antiferromagnets
Résumé
We investigate the magnetic properties of quasi one-dimensional quantum spin-S antiferromagnets. We use a combination of analytical and numerical techniques to study the presence of plateaux in the magnetization curve. The analytical technique consists in a path integral formulation in terms of coherent states. This technique can be extended to the presence of doping and has the advantage of a much better control for large spins than the usual bosonization technique. We discuss the appearance of doping-dependent plateaux in the magnetization curves for spin-S chains and ladders. The analytical results are complemented by a Density matrix Renormalization Group (DMRG) study for a trimerized spin-1/2 and anisotropic spin-3/2 doped chains.