Ground state of the quasi-1D correlated electronic system BaVS3

In this paper we review the salient features of the different instabilities exhibited by the quasi-1D system BaVS3 and show that there is a subtle interplay between the different phases stabilized. The analysis of the Peierls instability shows that the mobile dz² electrons are more localized than calculated because of their strong correlation with the localized e(t2g) electrons. The complex AF magnetic structure of BaVS3 incorporates the magnetization of the e(t2g) electrons with the Peierls pairing of the dz² electrons into magnetic singlets. Finally, we propose that the zig-zag disorder remaining after an incomplete orthorhombic phase transition could change the sign of the magnetic coupling and thus help to stabilize the canted ferromagnetism observed in non stoichiometric BaVS3−δ and Sr and Ba substituted compounds.