Date of this Version
Journal of Applied Physics
It is shown how the propagator formalism can be used to obtain the low‐temperature expansion of the free energy of an isotropic Heisenberg antiferromagnet. The lowest‐order terms in such an expansion can be calculated using the proper self‐energy evaluated at zero temperature. The analytic properties of this quantity are investigated by expressing it in terms of time ordered diagrams. The low‐temperature expansion of the free energy is shown to be of the form AT 4+BT 4+CT 8, where A, B, and C are given by Oguchi correctly to order 1/S. For spin ½ the term in 1/S 2 gives a 2% reduction in A for a body‐centered lattice.
Reprinted with permission from the Journal of Applied Physics. Copyright 1964, American Institute of Physics.
Harris, A. (1964). Low‐Temperature Properties of a Heisenberg Antiferromagnet. Journal of Applied Physics, 35 (3), 798-799. http://dx.doi.org/10.1063/1.1713477
Date Posted: 12 August 2015
This document has been peer reviewed.