Doping-induced magnetization plateaus

Abstract

The low-temperature magnetization process of antiferromagnetic spin- S chains doped with mobile spin- (S−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.