Volume 52, Number 4, November II 2000
|Page(s)||434 - 440|
|Section||Condensed matter: electronic structure, electrical, magnetic, and optical properties|
|Published online||01 September 2002|
A nonlinear σ-model approach
Dipartimento di Fisica, Università di Bologna, INFN and INFM
V.le Berti Pichat 6/2, I-40127, Bologna, Italy
2 Dipartimento di Matematica e Fisica and INFM, Università di Camerino I-62032 Camerino, Italy
Accepted: 18 September 2000
We present here a nonlinear sigma-model (NLσM) study of a spin-1 antiferromagnetic Heisenberg chain in an external commensurate staggered magnetic field. We find, already at the mean-field level, excellent agreement with recent and very accurate Density Matrix Renormalization Group (DMRG) studies, and that up to the highest values of the field for which a comparison is possible, for the staggered magnetization and the transverse spin gap. Qualitative but not quantitative agreement is found between the NLσM predictions for the longitudinal spin gap and the DMRG results. The origin of the discrepancies is traced and discussed. Our results allow for extensions to higher-spin chains that have not yet been studied numerically, and the predictions for a spin-2 chain are presented and discussed. Comparison is also made with previous theoretical approaches.
PACS: 75.10.Jm – Quantized spin models / 75.30.Cr – Saturation moments and magnetic susceptibilities / 75.40.Cx – Static properties (order parameter, static susceptibility, spin waves, spin diffusion, dynamic scaling, etc.)
© EDP Sciences, 2000
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.