Phys. Rev. B 72, 155441 (2005) [9 pages]Electronic structure and vibrational properties of Ba8Si46,Ba8AgnSi46−n, and Ba8AunSi46−nReceived 13 June 2005; revised 10 August 2005; published 28 October 2005 The electronic and vibrational structures of Ba8Si46 and Ba8MnSi46−n, where some of the framework Si were replaced by metal (M=Ag 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 Ba8Si46. 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 Ba8Si46 was found. © 2005 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevB.72.155441
DOI:
10.1103/PhysRevB.72.155441
PACS:
78.30.−j, 63.20.Dj, 63.20.Pw, 71.20.−b
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