Issue
EPL
Volume 86, Number 3, May 2009
Article Number 37005
Number of page(s) 6
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
DOI http://dx.doi.org/10.1209/0295-5075/86/37005
Published online 14 May 2009
EPL, 86 (2009) 37005
DOI: 10.1209/0295-5075/86/37005

Spin $\chem{3/2}$ dimer model

S. Rachel

Institut für Theorie der Kondensierten Materie, Universität Karlsruhe Postfach 6980, 76128 Karlsruhe, Germany, EU

rachel@tkm.uni-karlsruhe.de

received 3 February 2009; accepted in final form 9 April 2009; published May 2009
published online 14 May 2009

Abstract
We present a parent Hamiltonian for weakly dimerized valence bond solid states for arbitrary half-integral S. While the model reduces for S=1/2 to the Majumdar-Ghosh Hamiltonian, we discuss this model and its properties for S=3/2. Its degenerate ground state is the most popular toy model state for discussing dimerization in spin 3/2 chains. In particular, it describes the impurity-induced dimer phase in Cr8Ni as proposed recently. We point out that the explicit construction of the Hamiltonian and its main features apply to arbitrary half-integral spin S.

PACS
75.10.Pq - Spin chain models.
75.10.Dg - Crystal-field theory and spin Hamiltonians.
75.10.Jm - Quantized spin models.

© EPLA 2009