Crystal structure and charge order below the metal–insulator transition in the vanadium bronze β-SrV 6O 15

Abstract

Single crystal X-ray diffraction measurements were performed on one-dimensional mixed valence vanadium bronze β-SrV 6O 15 in which a metal–insulator transition exists at 170 K. Above 170 K the P2 1/ a structure with zigzag order of Sr in the tunnels of vanadium is confirmed. In the structure below 170 K, the P2 1/ a space group is retained with a b-axis threefold increase and a charge order appears. A bond valence sum analysis shows that the charge order may consist in clusters of V 4+ regularly spaced along 1D direction.