Eur. Phys. J. B 5, 565-569 (1998)
https://doi.org/10.1007/s100510050479

Spontaneous SU(2) symmetry breaking in one-dimensional quantum antiferromagnet^*

¹ B.I. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, Lenin Avenue 47, Kharkov 310164, Ukraine
² Kharkov State University, 4 Svobody Place, Kharkov, 310077, Ukraine

Corresponding author: ^a az@thp.uni-koeln.de

Received: 19 January 1998
Revised: 16 March 1998
Accepted: 17 March 1998
Published online: 15 October 1998

Abstract

We present a Bethe Ansatz based investigation of a one-dimensional (1D) Heisenberg spin chain in a real 3D crystal lattice. We have shown that due to an influence of the lattice distortion on a crystalline field of ligands of magnetic ions, a Heisenberg antiferromagnetic spin chain is unstable under the appearance of a magnetic anisotropy of the "easy-plane" type. The effects of an external magnetic field and nonzero temperature onto such a phase transition are studied.