Geometric origin of excess low-frequency vibrational modes in weakly connected amorphous solids

M. Wyart, S. R. Nagel, T. A. Witten

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Glasses have an excess number of low-frequency vibrational modes in comparison with most crystalline solids. We show that such a feature necessarily occurs in solids with low coordination. In particular, we analyze the density D(ω) of normal-mode frequencies ω and the nature of the low-frequency normal modes of a recently simulated system (O'HERN C., SILBERT L. E., LIU A. J. and NAGEL S. R., Phys. Rev. E, 68 (2003) 011306) comprised of weakly compressed spheres at zero temperature. We account for the observed a) convergence of D(ω) toward a non-zero constant as the frequency goes to zero, b) appearance of a low-frequency cutoff ω*, and c) power law increase of ω* with compression. We introduce a length scale l* which characterizes the vibrational modes that appear at ω*.

    Original languageEnglish (US)
    Pages (from-to)486-492
    Number of pages7
    JournalEurophysics Letters
    Volume72
    Issue number3
    DOIs
    StatePublished - Nov 1 2005

    ASJC Scopus subject areas

    • Physics and Astronomy(all)

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