The direct correlation function of a crystalline solid

Abstract

Direct correlation functions (DCFs), linked to the second functional derivative of the free energy with respect to the one-particle density, play a fundamental role in a statistical mechanics description of matter. This holds in particular for the ordered phases: DCFs contain information about the local structure including defects and encode the thermodynamic properties of crystalline solids; they open a route to the elastic constants beyond low temperature expansions. Via a numerical tour de force we have explicitly calculated for the first time the DCF of a solid: based on the fundamental measure concept we provide results for the DCF of a hard sphere crystal. We demonstrate that this function differs at coexistence significantly from its liquid counterpart - both in shape as well as in its order of magnitude - because it is dominated by vacancies. We provide evidence that the traditional use of liquid DCFs in functional Taylor expansions of the free energy is conceptually wrong and show that the emergent elastic constants are in good agreement with simulation-based results.

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Cited by in corpus (12)

• Noether's Theorem in Statistical Mechanics
• Why Noether's Theorem applies to Statistical Mechanics
• Perspective: How to overcome dynamical density functional theory
• Force density functional theory in- and out-of-equilibrium
• Noether-Constrained Correlations in Equilibrium Liquids
• Microscopic density-functional approach to nonlinear elasticity theory
• Active crystallization from power functional theory
• Elastic properties of Yukawa crystals
• Continuum mechanics for the elastic properties of crystals: Microscopic approach based on projection-operator formalism
• Structural properties of additive binary hard-sphere mixtures. III. Direct correlation functions
• Dynamical field theories for biaxial liquid crystals
• Elasticity in crystals with high density of local defects : insights from ultra-soft colloids