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

D. Zanchi (1) , A. Bjelis

1 LPTHE - Laboratoire de Physique Théorique et Hautes Energies

The spin density wave instabilities in the quasi-one-dimensional metal (TMTSF)_2ClO_4 are studied in the framework a matrix random phase approximation for intra-band and inter-band order parameters. Depending on the anion ordering potential V which measures the lattice doubling in the transverse direction, two different instabilities are possible. The SDW_0 state at low values of V is antiferromagnetic in b direction and has the 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 subfamily of chains. As V increases the ratio between 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 the metallic state can persist down to T=0.

Domaines: Autre [cond-mat.other]

D. Zanchi, A. Bjelis. New SDW phases in quasi-one-dimensional systems dimerized in the transverse direction. EPL - Europhysics Letters, 2001, 56, pp.596-602. ⟨hal-00007627⟩