PRESSURE TUNING OF THE CHARGE-DENSITY-WAVE IN THE HALOGEN-BRIDGED TRANSITION-METAL SOLID PT2BR6(NH3)(4)

We report the pressure dependence up to 95 kbar of Raman-active stretching modes in the quasi-one-dimensional MX chain solid Pt2Br6(NH3)4. The data indicate that a predicted pressure-induced insulator-to-metal transition does not occur, but are consistent with the solid undergoing either a three-dimensional structural distortion or a transition from a charge-density wave to another broken-symmetry ground state. We show that such a transition can be well modeled within a Peierls-Hubbard Hamiltonian. © 1994 The American Physical Society.