Abstract
The spontaneous dimerization of frustrated spin- 1/2 antiferromagnetic chains is studied via a microscopic approach based on a proper set of composite operators (i.e., pseudo-spin operators). Two approximation schemes are developed. Firstly, a spin-wave approximation is made via a Dyson-Maleev-like boson transformation. The ground-state properties and the triplet excitation spectra are obtained as functions of the coupling parameter. Secondly, a microscopic treatment, based on pseudo-spin operators, is formulated within the framework of the powerful, systematic coupled-cluster method (CCM). Comparison between various approximations is made. The advantage of the CCM for the purposes of systematic improvement is emphasized.
| Original language | English |
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| Pages (from-to) | 5965-5980 |
| Number of pages | 16 |
| Journal | Journal of Physics: Condensed Matter |
| Volume | 6 |
| Issue number | 30 |
| Publication status | Published - 1994 |