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Cut-off nonlinearities in the low-temperature vibrations of glasses and crystals

Mizuno, Hideyuki and Silbert, Leo and Sperl, Matthias and Mossa, Stefano and Barrat, Jean-Louis (2016) Cut-off nonlinearities in the low-temperature vibrations of glasses and crystals. Physical Review E, 93, 043314. American Physical Society. doi: 10.1103/PhysRevE.93.043314. ISSN 2470-0045.

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Official URL: https://doi.org/10.1103/PhysRevE.93.043314


We present a computer simulation study of glassy and crystalline states using the standard Lennard-Jones interaction potential that is truncated at a finite cutoff distance, as is typical of many computer simulations. We demonstrate that the discontinuity at the cutoff distance in the first derivative of the potential (corresponding to the interparticle force) leads to the appearance of cutoff nonlinearities. These cutoff nonlinearities persist into the very-low-temperature regime thereby affecting low-temperature thermal vibrations, which leads to a breakdown of the harmonic approximation for many eigenmodes, particularly for low-frequency vibrational modes. Furthermore, while expansion nonlinearities which are due to higher order terms in the Taylor expansion of the interaction potential are usually ignored at low temperatures and show up as the temperature increases, cutoff nonlinearities can become most significant at the lowest temperatures. Anharmonic effects readily show up in the elastic moduli which not only depend on the eigenfrequencies, but are crucially sensitive to the eigenvectors of the normal modes. In contrast, those observables that rely mainly on static structural information or just the eigenfrequencies, such as the vibrational density of states, total potential energy, and specific heat, show negligible dependence on the presence of the cutoff. Similar aspects of nonlinear behavior have recently been reported in model granular materials, where the constituent particles interact through finite-range, purely repulsive potentials. These nonlinearities have been ascribed to the nature of the sudden cutoff at contact in the force law. As a consequence, we demonstrate that cutoff nonlinearities emerge as a general feature of ordered and disordered solid state systems interacting through truncated potentials.

Item URL in elib:https://elib.dlr.de/110338/
Document Type:Article
Title:Cut-off nonlinearities in the low-temperature vibrations of glasses and crystals
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Mossa, Stefanouniv. grenoble alpes, inac-spram, f-38000 grenoble, franceUNSPECIFIEDUNSPECIFIED
Barrat, Jean-Louisuniv. grenoble alpes, liphy, f-38000 grenoble, franceUNSPECIFIEDUNSPECIFIED
Date:April 2016
Journal or Publication Title:Physical Review E
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In ISI Web of Science:Yes
Page Range:043314
Publisher:American Physical Society
Keywords:molecular Dynamics simulation
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Research under Space Conditions
DLR - Research area:Raumfahrt
DLR - Program:R FR - Research under Space Conditions
DLR - Research theme (Project):R - Model systems
Location: Köln-Porz
Institutes and Institutions:Institute of Materials Physics in Space
Deposited By: Sperl, Matthias
Deposited On:09 Jan 2017 15:16
Last Modified:17 Mar 2021 13:40

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