Abstract
The electronic and vibrational structures of and , where some of the framework Si were replaced by metal ( or Au) have been studied. Theoretical calculations show that the nature of chemical bonding of the substituted clathrates and their vibrational properties are fundamentally different from . Low-frequency vibrations associated with the motions of Ba in the large cages and the framework metals have been identified from their Raman spectra. A surprisingly large contribution of the low-frequency modes, particularly those which arise from the Ba vibrations in the large cages, to the electron-phonon coupling parameter in was found.
3 More- Received 13 June 2005
DOI:https://doi.org/10.1103/PhysRevB.72.155441
©2005 American Physical Society