1. Magnetic Double Structure for S=1, 1/2 Mixed-Spin Systems
- Author
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Takushima, Y., Koga, A., and Kawakami, N.
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
We investigate the zero-temperature and the finite-temperature properties of the two-dimensional antiferromagnetic quantum spin system composed of the s=1/2 and s=1 spins. The spin excitation spectrum as well as the thermodynamic quantities are computed by means of the Schwinger-boson mean-field theory. We discuss how the magnetic double structure with the gapful and the gapless excitations is generated, and apply the results systematically to the Haldane gap system in a staggered magnetic field and also to the weakly coupled ferrimagnetic mixed-spin chains. It is confirmed that the results obtained are consistent with the experiments for the quasi-one-dimensional Haldane compounds $R_2 \rm BaNiO_5$., Comment: 7 pages, REVTeX, 11 figures, to appear in P.R.B
- Published
- 2000
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