DOI: 10.1209/epl/i2001-00562-1


Europhys. Lett., 56 (4) , pp. 596-602 (2001)

New SDW phases in quasi-one-dimensional systems dimerized in the transverse direction

D. Zanchi¹ and A. Bjelis<sup>2

1</sup>  Laboratoire de Physique Théorique et Hautes Energies Universités Paris VI Pierre et Marie Curie - Paris VII Denis Diderot 2 Place Jussieu, 75252 Paris Cédex 05, France
²  Department of Physics, Faculty of Science, University of Zagreb P.O. Box 331, 10002 Zagreb, Croatia

(Received 31 May 2001; accepted in final form 3 September 2001)

Abstract
The spin density wave instabilities in the quasi-one-dimensional metal (TMTSF)₂ClO₄ are studied in the framework of a matrix random phase approximation for intraband and interband order parameters. Depending on the anion ordering potential V which measures the lattice doubling in the transverse direction, two different instabilities are possible. The SDW₀ state at low values of V is antiferromagnetic in the b direction and has a critical temperature that decreases rapidly with V. The degenerated states SDW, stable at higher values of V, are superpositions of two magnetic orders, each one on its sub-family of chains. As V increases, the ratio between the two components of SDW tends to zero and the critical temperature increases asymptotically towards that of SDW instability for a system having perfect nesting and no anion order. At intermediate V, i.e. between the phases SDW₀ and SDW, the metallic state can persist down to T=0.

PACS
75.30.Fv - Spin-density waves.
75.10.Lp - Band and itinerant models.
74.70.Kn - Organic superconductors.


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