X-ray anomalous scattering investigation of BaVS3 -: art. no. 033102

The quasi-one-dimensional conductor BaVS3 undergoes a metal-insulator transition at T-MI=70 K accompanied by a formation of superstructure doubling the chain periodicity and a magnetic transition at T-X=30 K. We present an anomalous x-ray scattering investigation of the charge-density wave (CDW) satellite reflections at the V K-edge. Our study shows that no charge disproportionation larger than 0.01 electron occurs at T-MI and T-X. We interpret this result by the stabilization of two out-of phase CDW's for the d(z)(2) and e(t(2g)) electrons, which induces an orbital ordering while reducing the intrachain Coulomb repulsions.