Thermodynamically Stable One-Component Quasicrystals: A Density-Functional Survey of Relative Stabilities

TL;DR

This study uses density-functional and thermodynamic perturbation theories to predict the stability of one-component quasicrystals at finite temperatures, highlighting the role of vibrational and interaction effects.

Contribution

It provides a comprehensive thermodynamic survey of quasicrystal stability using effective metallic pair potentials, extending prior ground-state analyses.

Findings

Thermodynamically stable quasicrystals are predicted near mechanical stability limits.

Stability is linked to vibrational stiffness and medium- to long-range interactions.

Results support and extend previous lattice-sum studies.

Abstract

A combination of classical density-functional theory and thermodynamic perturbation theory is applied to a survey of finite-temperature trends in the relative stabilities of one-component crystals and quasicrystals interacting via effective metallic pair potentials derived from pseudopotential theory. Comparing the free energies of several periodic crystals and rational approximant models of quasicrystals over a range of pseudopotential parameters, thermodynamically stable quasicrystals are predicted for parameters approaching the limits of mechanical stability of the crystal structures. Quasicrystalline stability is attributed to vibrational stiffness and energetically favorable medium- and long-range interactions. The results support and significantly extend conclusions of previous ground-state lattice-sum studies.