Physical review. B, Condensed matter
Magnetization plateau in the S= 12 Heinsenberg spin chain with next-nearest-neighbor and alternating nearest-neighbor interactions
Keisuke Totsuka
Abstract
The magnetization process of the $S=1/2$ Heisenberg chain with next-nearest-neighbor (NNN) and alternating nearest-neighbor interactions is investigated using the bosonization technique. The existence of the NNN interaction is shown to stabilize a ``diluted'' dimer order at magnetization ${m}^{z}=1/4,$ leading to a plateau, where two degenerate ground states appear. Effective Hamiltonians describing the low-energy physics in the vicinity of the ${m}^{z}=1/4$ plateau are also presented. The analogy to metal-insulator transitions is discussed briefly.