| dc.description |
Using the full-potential linearized augmented-plane-wave (FLAPW) method, the mechanism of the rutile-CaCl<sub>2</sub> phase transition of RuO<sub>2</sub> and the phase stability of β-PtO<sub>2</sub> are investigated. The local density functional calculations predict quantities such as lattice constants, bulk moduli, and phonon frequencies in good agreement with experiment. The pressure-induced phase transition in RuO<sub>2</sub> appears to be driven by the strong repulsion between O-O and Ru-O along the diagonal direction in the xy-plane. By contrast, a strong hybridization between the Pt 5d and O 2p states is responsible for the stability of the β-PtO<sub>2</sub> structure, for which a pseudo-gap (instead of the strong peak for the rutile-PtO<sub>2</sub>) is opened at the Fermi level due to the rotation of the PtO<sub>6</sub> octahedra. |
