Effect of a Spin-1/2 Impurity on the Spin-1 Antiferromagnetic Heisenberg Chain
Abstract
Low-lying excited states as well as the ground state of the spin-1 antiferro- magnetic Heisenberg chain with a spin-1/2 impurity are investigated by means of a variational method and a method of numerical diagonalization. It is shown that 1) the impurity spin brings about massive modes in the Haldane gap, 2) when the the impurity-host coupling is sufficiently weak, the phenomenological Hamiltonian used by Hagiwara {\it et al.} in the analysis of ESR experimental results for NENP containing a small amount of spin-1/2 Cu impurities is equivalent to a more realistic Hamiltonian, as far as the energies of the low-lying states are concerned, 3) the results obtained by the variational method are in semi-quantitatively good agreement with those obtained by the numerical diagonalization.
Keywords
Cite
@article{arxiv.cond-mat/9310061,
title = {Effect of a Spin-1/2 Impurity on the Spin-1 Antiferromagnetic Heisenberg Chain},
author = {Makoto Kaburagi and Takashi Tonegawa},
journal= {arXiv preprint arXiv:cond-mat/9310061},
year = {2009}
}
Comments
11 pages, plain TeX (Postscript figures are included), KU-CCS-93-002