Probing the non-Debye low-frequency excitations in glasses through random pinning.

Angelani, Luca; Paoluzzi, Matteo; Parisi, Giorgio; Ruocco, Giancarlo · Proc Natl Acad Sci U S A · 2018

basic_science · Level V

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Abstract

We investigate the properties of the low-frequency spectrum in the density of states [Formula: see text] of a 3D model glass former. To magnify the non-Debye sector of the spectrum, we introduce a random pinning field that freezes a finite particle fraction to break the translational invariance and shifts all of the vibrational frequencies of the extended modes toward higher frequencies. We show that non-Debye soft localized modes progressively emerge as the fraction <i>p</i> of pinned particles increases. Moreover, the low-frequency tail of [Formula: see text] goes to zero as a power law [Formula: see text], with [Formula: see text] and [Formula: see text] above a threshold fraction [Formula: see text].