2005/01/10 by B. A. Ivanov, V. E. Kireev
Physics and Astronomy · #cond-mat.mes-hall
published as JETP 94, 270 -- 282 (2002) · 12 pages, 1 table
arxiv created 2005/01/10 · arxiv updated 2009/12/01
For a two-sublattice antiferromagnet the Lagrangian is constructed taking into account Berry phase whose form is matched to the quantum-mechanical Heisenberg Hamiltonian. Tunnel effects are analyzed taking into account the crystallographic symmetry and possible types of the Dzyaloshinskii-Moriya interaction. It is shown that, when the real magnetic symmetry and the Dzyaloshinskii-Moriya interaction are taken into consideration, the effects of a destructive instanton interference and the suppression of macroscopic quantum tunneling can play an essential role. It also may lead to a periodic dependence of the ground-state level splitting on the Dzyaloshinskii-Moriya interaction constant; the magnitude of this splitting is calculated.