Glassy dynamics and local crystalline order in two-dimensional amorphous silica

Date
2025-09-19, 13:00

NOMATEN HYBRID-SEMINAR

online: https://meet.goto.com/NCBJmeetings/nomaten-seminar
In-person: NOMATEN seminar room (102)

Friday, September 19th  2025 1 PM (CET)

Glassy dynamics and local crystalline order in two-dimensional amorphous silica

Marco Dirindin
University of Trieste, Italy

 

Abstract:

Over the last 20 years, the study of low-dimensional systems has been extremely prolific, giving rise to new technological applications and developments for fundamental research. Despite the vast knowledge we now have about two-dimensional crystalline materials, little is known about their amorphous counterparts.

In this talk, I will discuss the structure and dynamics of a simple model of the silica bilayer, one of the first two-dimensional amorphous materials ever synthesized. We use a structure-matching approach to improve the effective potential used to describe the system [1], focusing on the reproduction of the network structure of the experimental samples. We then carefully study the dynamics of the optimized model, paying particular attention to the peculiarities of two-dimensional materials, such as Mermin-Wagner fluctuations. At low temperatures, the system behaves like a highly viscous liquid, with heterogeneous dynamics and relaxation times that follow an Arrhenius law. Surprisingly, we observe a concomitant appearance of transient crystallites, which at the lowest accessible temperature are nanometric in size [2].

These results, which have little correspondence in three-dimensional amorphous systems, shed new light on the physics of two-dimensional network-forming materials.

 

References

[1] Projesh Kumar Roy, Markus Heyde, Andreas Heuer, Modelling the atomic arrangement of amorphous 2D silica: a network analysis, Phys. Chem. Chem. Phys., 20, 14725 (2018)

[2] Marco Dirindin, Daniele Coslovich, Glassy Dynamics and Local Crystalline Order in Two-Dimensional Amorphous Silica, J. Phys. Chem. B, 129, 3, 1095–1108 (2025)

 

Bio:

Marco Dirindin is a third-year PhD at the University of Trieste under the supervision of Daniele Coslovich and Maria Peressi. His work focuses on the physics of two-dimensional network-forming materials, analyzed using both ab initio methods and large-scale molecular dynamics simulations.

 

 

 

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This project has received funding from the European Union Horizon 2020 research and innovation
programme under grant agreement No 857470 and from European Regional Development Fund
via Foundation for Polish Science International Research Agenda PLUS programme grant
No MAB PLUS/2018/8.
Poland
The project is co-financed from the state budget within the framework of the undertaking of the Minister of Science and Higher Education "Support for the activities of Centers of Excellence established under Horizon 2020".

Grant: 5 143 237,70 EUR
Total value: 29 971 365,00 EUR
Date of signing the funding agreement: December 2023

The purpose of the undertaking is to support entities of the higher education and science system that have received funding from the European Union budget in the competition H2020-WIDESPREAD-2018-2020/WIDESPREAD-01-2018-2019: Teaming Phase 2. in the preparation, implementation and updating of activities, maintenance of material resources necessary for carrying out activities, acquisition and modernization of scientific and research apparatus, maintenance and development of personnel potential necessary for the implementation of activities, and dissemination of the results of scientific activities.