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Published on: August 22, 2017
Dynamical structure factor in disordered systems
Martin-Mayor1, Parisi, Verrocchio
1Dipartimento di Fisica, Universita di Roma "La Sapienza," INFN Sezione di Roma - INFM Unita di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy.
Abstract:
We study the spectral width as a function of the external momentum for the dynamical structure factor of a disordered harmonic solid, considered as a toy model for supercooled liquids and glasses. In the contexts of both the single-link coherent potential approximation and a single-defect approximation, two different regimes are clearly identified: if the density of states at zero energy is zero, the usual p(4) law is recovered for small momentum. On the contrary, if the disorder induces a nonvanishing density of states at zero energy, a linear behavior is obtained. The dynamical structure factor is numerically calculated in lattices as large as 96(3) and satisfactorily agrees with the analytical computations.
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