CMSP Seminar (Atomistic Simulation Seminar Series) 2 December, 11:00AM, by John Russo

[CMSP Seminars Secretariat]

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CMSP Seminar (Atomistic Simulation Seminar Series)
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*Monday, 2 December 2024, 11:00AM*
*/Luigi Stasi Seminar Room (Leonardo Building, 1st floor)/*/
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/Zoom: 
https://zoom.us/meeting/register/tJAocuqrrzgtHtZyIf_66Klrc6ReCitsEnqJ<https://zoom.us/meeting/register/tJEucu2tqT8uGNYvpgXUFeLDWBQUA5z0bwV0>
<https://zoom.us/meeting/register/tJAocuqrrzgtHtZyIf_66Klrc6ReCitsEnqJ> /

Speaker:*  John Russo*** (Sapienza Università di Roma)

Title: *Towards Glasses with Permanent Stability *

Abstract:

/The thermodynamic fate of any glassy material is devitrification, a 
process that compromises their structural integrity and limits their 
functionality. However, recent experimental advances have enabled the 
preparation of ultrastable glasses, which exhibit exceptional 
thermodynamic and kinetic stability, making them indispensable for 
applications in pharmaceuticals, optical media, and cryogenic solutions. 
In this work, we present two numerical strategies to prepare and 
investigate ultrastable glasses.
The first approach involves suppressing volume fraction inhomogeneities 
by modifying the size distribution of particles [1]. Using this method, 
we demonstrate that devitrification can be effectively avoided, 
establishing a direct link between mechanical stability and a simple 
structural property—the distribution of local volume fractions. This 
insight provides a predictive framework for assessing glass stability 
and reveals a structural mechanism underlying avalanche devitrification.
The second approach employs molecular dynamics simulations of vapor 
deposition, showing that ultrastable glasses achieve enhanced stability 
through the formation of locally favored structures (LFS). By examining 
various glass-forming models, from binary mixtures [2] to strong glasses 
with directional bonding [3], we uncover the kinetic pathways that 
facilitate the formation of crystalline nuclei just below the surface. 
Together, these methods offer complementary perspectives on the design 
and stability of ultrastable glasses.

References
[1] T. Yanagishima, J. Russo, R.P.A. Dullens, H. Tanaka, Phys. Rev. 
Lett., 127, (2021)
[2] F Leoni, F Martelli, CP Royall, J Russo, Phys. Rev. Lett. 130, 
198201 (2023)
[3] F Leoni, F Martelli, J Russo, J Phys Chem Lett 15, 8444 (2024)


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http://www.ictp.it/research/cmsp.aspx

The Abdus Salam International Centre for Theoretical Physics
https://www.ictp.it/

    
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