Yielding under compression and the polyamorphic transition in silicon

Abstract: We investigate the behavior of amorphous silicon under hydrostatic compression using molecular simulations. During compression, amorphous silicon undergoes a transformation from a low-density to a high-density structure. Depending on the temperature and the compression rate, the transformation occurs in a pressure range between 6 and 16 GPa. Ensemble-averaged density and elastic constants change discontinuously across the transition. Densification of individual glassy samples occurs through a series of discrete plastic events, each of which is accompanied by a vanishing shear modulus. This is the signature of a series of elastic instabilities, similar to shear transformation zones observed during shear yielding of glasses. We compare the structure obtained during compression with a quasiequilibrium form of amorphous silicon obtained by quenching a melt at constant pressure. This gives structures identical to compression at low and high pressure, but the transition between low- and high-pressure structures occurs gradually rather than discontinuously. Our observations indicate that the polyamorphic transition has the characteristics of a yield transition that occurs under compression instead of shear

Location
Deutsche Nationalbibliothek Frankfurt am Main
Extent
Online-Ressource
Language
Englisch
Notes
ISSN: 2475-9953

Event
Veröffentlichung
(where)
Freiburg
(who)
Universität
(when)
2023
Creator
Grießer, Jan
Moras, Gianpietro
Pastewka, Lars

DOI
10.1103/physrevmaterials.7.055601
URN
urn:nbn:de:bsz:25-freidok-2410249
Rights
Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
Last update
15.08.2025, 7:27 AM CEST

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Associated

Time of origin

  • 2023

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