Geometric frustration is an approach to the glass transition based upon the consideration of locally favoured structures (LFS), which are geometric motifs which minimise the local free energy. Geometric frustration proposes that a transition to a crystalline state is frustrated because these LFS do not tile space. However, this concept is based on icosahedra which are not always the LFS for a given system. The LFS of the popular Kob-Andersen (KA) model glassformer are the bicapped square antiprism, which does tile space. Such a LFS-crystal is indeed realised in the Al2Cu structure, which is predicted to be a low energy state for the KA model with a 2:1 composition. We, therefore, hypothesise that upon changing the composition in the KA model towards 2:1, geometric frustration may be progressively relieved, leading to larger and larger domains of LFS which would ultimately correspond to the Al2Cu crystal. Remarkably, rather than an increase, upon changing composition we find a small decrease in the LFS population, and the system remains impervious to nucleation of LFS crystals. We suggest that this may be related to the composition of the LFS, as only a limited subset is compatible with the crystal. We further demonstrate that the Al2Cu crystal will grow from a seed in the KA model with 2:1 composition and identify the melting temperature to be 0.447(2).
Skip Nav Destination
Article navigation
28 July 2015
Research Article|
July 24 2015
The nature of geometric frustration in the Kob-Andersen mixture
Peter Crowther
;
Peter Crowther
1
H.H. Wills Physics Laboratory
, Tyndall Avenue, Bristol, United Kingdom
2School of Chemistry,
University of Bristol
, Cantock’s Close, Bristol, United Kingdom
Search for other works by this author on:
Francesco Turci
;
Francesco Turci
a)
1
H.H. Wills Physics Laboratory
, Tyndall Avenue, Bristol, United Kingdom
Search for other works by this author on:
C. Patrick Royall
C. Patrick Royall
1
H.H. Wills Physics Laboratory
, Tyndall Avenue, Bristol, United Kingdom
2School of Chemistry,
University of Bristol
, Cantock’s Close, Bristol, United Kingdom
3
Centre for Nanoscience and Quantum Information
, Tyndall Avenue, Bristol, United Kingdom
Search for other works by this author on:
a)
Author to whom correspondence should be addressed. Electronic mail: f.turci@bristol.ac.uk
J. Chem. Phys. 143, 044503 (2015)
Article history
Received:
April 27 2015
Accepted:
July 13 2015
Citation
Peter Crowther, Francesco Turci, C. Patrick Royall; The nature of geometric frustration in the Kob-Andersen mixture. J. Chem. Phys. 28 July 2015; 143 (4): 044503. https://doi.org/10.1063/1.4927302
Download citation file:
Sign in
Don't already have an account? Register
Sign In
You could not be signed in. Please check your credentials and make sure you have an active account and try again.
Sign in via your Institution
Sign in via your InstitutionPay-Per-View Access
$40.00