Yielding under compression and the polyamorphic transition in silicon
arXiv:2302.11936 · doi:10.1103/PhysRevMaterials.7.055601
Abstract
We investigate the behavior of amorphous silicon under hydrostatic compression using molecular simulations. During compression, amorphous silicon undergoes a discontinuous nonequilibrium transition from a low-density to a high-density structure at a pressure of around -~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 near-equilibrium form of amorphous silicon obtained by quenching a melt at constant pressure. This gives structures identical to nonequilibrium compression at low and high pressure, but the transition between them occurs gradually rather than discontinuously. Our observations indicate that the polyamorphic transition is of a nonequilibrium nature, and it has the characteristics of a yield transition that occurs under compression instead of shear.
arXiv comment9 pages, 6 figures
References in corpus (19)
- Dynamics of Viscoplastic Deformation in Amorphous Solids
- Amorphous Systems in Athermal, Quasistatic Shear
- Machine learning a general purpose interatomic potential for silicon
- Local elasticity map and plasticity in a model Lennard-Jones glass
- Continuum limit of amorphous elastic bodies: A finite-size study of low frequency harmonic vibrations
- A random critical point separates brittle and ductile yielding transitions in amorphous materials
- Universal Breakdown of Elasticity at the Onset of Material Failure
- Predicting plasticity in disordered solids from structural indicators
- A study of the static yield stress in a binary Lennard-Jones glass
- Liquid-liquid critical point in supercooled silicon
- Measuring Spatial Distribution of Local Elastic Modulus in Glasses
- Liquid-liquid transition in supercooled silicon determined by first-principles simulation
- Shear bands as manifestation of a criticality in yielding amorphous solids
- Mechanical Yield in Amorphous Solids: a First-Order Phase Transition
- On the Strength of Glasses
- A simple and broadly-applicable definition of shear transformation zones
- Correlations of non-affine displacements in metallic glasses through the yield transition
- Solid-phase silicon homoepitaxy via shear-induced amorphization and recrystallization
- Amorphous silicon under mechanical shear deformations: shear velocity and temperature effects