Eur. Phys. J. B 5, 705-717 (1998)
https://doi.org/10.1007/s100510050494

Novel massive ground states of spin chains in a magnetic field^*

The Institute of Physical and Chemical Research (RIKEN), Wako, Saitama, 351-01, Japan

Corresponding author: ^a totsuka@postman.riken.go.jp

Received: 16 February 1998
Revised: 20 April 1998
Accepted: 30 April 1998
Published online: 15 October 1998

Abstract

Novel massive quantum states appearing in spin chains under a strong magnetic field are discussed. These states lead to plateaus in magnetization curves. When the systems are axially symmetric and the field is applied parallel to the symmetry-axis, the phenomena are analogous to metal-insulator transitions. Striking features of the plateau phenomena - exactness and rationality -are explained as consequences the commensurability condition to the underlying lattice. The effects of the planar anisotropy are also discussed in detail.