Order Parameter in Quantum Antiferromagnets
1989; Physical Society of Japan; Volume: 58; Issue: 11 Linguagem: Inglês
10.1143/jpsj.58.3894
ISSN1347-4073
AutoresT. A. Kaplan, Peter Horsch, Wolfgang von der Linden,
Tópico(s)Magnetic properties of thin films
ResumoWe discuss the nature of symmetry breaking in quantum antiferromagnets. We show that published arguments concerning the order parameter for the 2d s =1/2 Heisenberg antiferromagnet have to be reconsidered. These had led to \(\sqrt{3}\) and 1 for the ratio r of the mean z -component m of the staggered spin per particle m s z in an infinitesimal staggered field B , to the r.m.s. value m 0 of m s z with B =0, in the thermodynamic limit. We give arguments which put doubt on both values. Also we prove r ≧1, given m 0 ≠0.
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