arXiv:cond-mat/9907258 · Physical Review Letters
Doping-Induced Magnetization Plateaus
Holger Frahm, Constantin Sobiella
Abstract
The low-temperature magnetization process of antiferromagnetic spin- $S$ chains doped with mobile spin- $(S\ensuremath{-}1/2)$ carriers is studied in an exactly solvable model. For sufficiently high magnetic fields the system is in a metallic phase with a finite gap for magnetic excitations. In this phase, which exists for a large range of carrier concentrations $x$, the zero-temperature magnetization is determined by $x$ alone. This leads to plateaus in the magnetization curve at a tunable fraction of the saturation magnetization. The critical behavior at the edges of these plateaus is studied in detail.