Computer simulations of glasses: the potential energy landscape

Abstract

Abstract. We review the current state of research on glasses, discussing the theoretical background and computational models employed to describe them. This article focuses on the use of the potential energy landscape (PEL) paradigm to account for the phenomenology of glassy systems, and the way in which it can be applied in simulations and the interpretation of their results. This article provides a broad overview of the rich phenomenology of glasses, followed by a summary of the theoretical frameworks developed to describe this phenomonology. We discuss the background of the PEL in detail, the onerous task of how to generate computer models of glasses, various methods of analysing numerical simulations, and the literature on the most commonly used model systems. Finally, we tackle the problem of how to distinguish a good glass former from a good crystal former from an analysis of the PEL. In summarising the state of the potential energy landscape picture, we develop the foundations for new theoretical methods that allow the ab initio prediction of the glass-forming ability of new materials by analysis of the PEL.

Anti-Aging in Ultrastable Metallic Glasses

“…Besides, organic USGs show a decreased enthalpy which seems to be not the case for their metallic counterpart [5,6]. With respect to conventional glasses, USGs are considered to be in a lower state in the potential energy landscape (PEL) [7][8][9], which is reached thanks to enhanced atomic mobility during fabrication process [10]. This deep position in the PEL is not accessible on practical timescales through classical methods as for example long annealing [3,11].…”

“…In the MGs, we see the typical aging with an increase of τ upon annealing. We may understand this behavior within the framework of the PEL [8,9]. Conventional MGs are known to be located in an energetically high basin in the PEL and thus can relax down by annealing, leading towards increased relaxation times [2,4,10,11,14].…”

Relaxation dynamics of glasses along a wide stability and temperature range

“…One of the biggest challenges in condensed matter physics is the understanding of amorphous systems, which lack the long range order of crystalline materials 1 2 3 4 5 . In spite of it, glasses are ubiquitous in our day life and many materials with technological significance display disordered atomic or molecular arrangements 1 .…”

“…The relaxation time of the liquid increases exponentially during cooling, at a pace determined by its fragile or strong nature. In the laboratory time scale, around certain value of the relaxation time, the molecules do not have enough time to explore the complete configurational space and get trapped inside local energy minima, forming a glass 1 2 3 4 5 . Below this temperature, upon further cooling, the relaxation time of the glass follows a much softer Arrhenius-like expression 6 .…”

Systematic study of glass transition in low-molecular phthalonitriles: Insight from computer simulations

“…Although substantial progress has been made in recent years to understand the role of intramolecular barriers, local structure, and time and length scales in glass-forming liquids, many questions still remain unanswered even for relatively easy model systems. [1][2][3][4][5] From the experimentalists' viewpoint, the main challenges are associated with determination of individual molecular coordinates. Only very recently it became possible to resolve individual atoms 6,7 and only in the surface layer, the dynamics of which are generally not representative for the bulk material.…”