High-pressure resistivity and x-ray diffraction have been measured on La0.85MnO3-d. At low pressures the metal-insulator transition temperature (TMI) increases linearly with pressure up to a critical pressure, P* ~ 3.4 GPa, which is followed by reduction of TMI with increasing pressure. Analysis of the bond distances and bond angles reveal that a bandwidth increase drives the in-crease of TMI for pressure below P*. The reduction of TMI at higher pressures is found to result from Jahn-Teller distortions of the MnO6 octahedra. The role of anharmonic interatomic potential is discussed.
Categories: cond-mat.mtrl-sci