Department of Physics Papers

Document Type

Journal Article

Date of this Version

3-1964

Publication Source

Journal of Applied Physics

Volume

35

Issue

3

Start Page

798

Last Page

799

DOI

10.1063/1.1713477

Abstract

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.

Copyright/Permission Statement

Reprinted with permission from the Journal of Applied Physics. Copyright 1964, American Institute of Physics.

Comments

At the time of publication, author A. Brooks Harris was affiliated with Duke University. Currently, he is a faculty member in the Physics Department at the University of Pennsylvania.

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Date Posted: 12 August 2015

This document has been peer reviewed.