Uniaxially anisotropic antiferromagnets in a field along the
Selke, W., Holtschneider, M., Leidl, R., Wessel, S., and Bannasch,G.
Institut für Theoretische Physik, Technische Hochschule Aachen, Aachen, Germany;
Department of Physics, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
Institut für Theoretische Physik, Universität Stuttgart, Stuttgart, Germany
Uniaxially anisotropic antiferromagnets in a field along the easy axis
are studied with
the help of ground state considerations and Monte Carlo
simulations. For classical models, the XXZ model as well as variants,
we analyze the role of non--collinear spin configurations of biconical
type interpolating between the well--known antiferromagnetic
and spin--flop structures. Possible experimental applications
to layered cuprate antiferromagnets are discussed. Finally, results
of quantum Monte Carlo simulations for the $S$=1/2 XXZ model on a
square lattice are presented, and compared
with previous findings.