Front-Mediated Melting of Isotropic Ultrastable Glasses

Elijah Flenner (1) , Ludovic Berthier (2) , Patrick Charbonneau (3) , Christopher J. Fullerton (2, 4)

1 Department of Chemistry, Colorado State University
2 L2C - Laboratoire Charles Coulomb
3 Duke University [Durham]
4 University of Oxford

Ultrastable vapor-deposited glasses display uncommon material properties. Most remarkably, upon heating they are believed to melt via a liquid front that originates at the free surface and propagates over a mesoscopic crossover length, before crossing over to bulk melting. We combine swap Monte Carlo with molecular dynamics simulations to prepare and melt isotropic amorphous films of unprecedendtly high kinetic stability. We are able to directly observe both bulk and front melting, and the crossover between them. We measure the front velocity over a broad range of conditions, and a crossover length scale that grows to nearly $400$ particle diameters in the regime accessible to simulations. Our results disentangle the relative roles of kinetic stability and vapor deposition in the physical properties of stable glasses.

Domaines: Matière Molle [cond-mat.soft]; Science des matériaux [cond-mat.mtrl-sci]

Elijah Flenner, Ludovic Berthier, Patrick Charbonneau, Christopher J. Fullerton. Front-Mediated Melting of Isotropic Ultrastable Glasses. Physical Review Letters, 2019, 123 (17), pp.175501. ⟨10.1103/PhysRevLett.123.175501⟩. ⟨hal-02358763⟩