High-pressure magnetic and structural properties of TiOX (X=Cl, Br)

Abstract We report high-pressure diffraction and magnetization measurements to demonstrate that the partial collapse of electronic gap at high-pressure insulator to metal transition reported in TiOCl (C. Kuntscher et al. Phys. Rev. B 74 184402 (2006).) corresponds to a Ti 3+ –Ti 3+ dimerization at room temperature within the space group P 2 1 / m . The shortest Ti–Ti distance is comparable to that of the Ti metal, but a Peierls-like distortion prevents a metallic behaviour.