The absence of crystallization on supercooling in a single component system of particles interacting through the harmonic-repulsive potential. A possible formation of a quasicrystal at a different value of the density

TL;DR

This study uses molecular dynamics to explore supercooling and crystallization behaviors in a single-component harmonic-repulsive particle system, revealing unusual supercooled states and potential quasicrystal formation at specific densities.

Contribution

It reports novel observations of supercooled liquids that do not crystallize and suggests possible quasicrystal formation in a simple harmonic-repulsive potential system.

Findings

Supercooled liquids that do not crystallize over long MD runs.

Crystallization into chain and columnar structures at certain densities.

Potential formation of quasicrystalline structures in a simple potential system.

Abstract

In this note, we report about two, as it seems to us, rather unusual observations made in molecular dynamics simulations of the single component systems of particles interacting through the harmonic-repulsive pair potential in 3D. In particular, at some densities, we observed deeply supercooled liquid states which did not exhibit crystallization in rather long MD runs. This observation is unusual because usually liquids formed by particles of only one type rather readily crystallize on supercooling. At a different value of the density we observed crystallization of the liquid into a state formed by chains (or lines) of particles which organize themselves into columns in such a way that each column is formed by seven lines of particles. Alternatively, one can think that each such column is formed by three alternating helical coils. In our view, it is possible that the overall structure that crystallizes from the liquid at this density is quasicrystalline. If it is indeed the case, then this observation is unusual because, as far as we understand, it is not expected, at present, that quasicrystalline structures can form in such a simple potential as harmonic-repulsive potential. Investigations related to the presumable phase diagram of the particles interacting through the harmonic-repulsive potential have been reported in [J. Chem. Phys. {\bf 134}, 044903 (2011)]. Our results appear to be at odds with some of the results presented there.