Europhys. Lett.
Volume 69, Number 3, February 2005
Page(s) 447 - 453
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 24 December 2004
Europhys. Lett., 69 (3), pp. 447-453 (2005)
DOI: 10.1209/epl/i2004-10361-8

The spin-SAF transition in $\chem{NaV_{2}O_{5}}$ induced by spin-pseudospin coupling

C. Gros1 and G. Y. Chitov1, 2

1  Fakultät 7, Theoretische Physik, University of the Saarland 66041 Saarbrücken, Germany
2  Department of Physics and Astronomy, Laurentian University 935 Ramsey Lake Road, Sudbury, Ontario P3E 2C6, Canada

received 2 September 2004; accepted in final form 23 November 2004
published online 24 December 2004

We present microscopic estimates for the spin-spin and spin-pseudospin interactions of the quarter-filled ladder compound $\chem{NaV_{2}O_{5}}$, obtained by exactly diagonalizing appropriate clusters of the underlying generalized Hubbard Hamiltonian. We present evidence for a substantial interladder spin-pseudospin interaction term which would allow simultaneously for the superantiferroelectric (SAF) charge (pseudospin) ordering and spin dimerization. We discuss the values of the coupling constants appropriate for $\chem{NaV_{2}O_{5}}$ and deduce the absence of a soft antiferroelectric mode.

75.10.Jm - Quantized spin models.
75.40.Mg - Numerical simulation studies.

© EDP Sciences 2005