Synthetic Diamond and Wurtzite Structures Self-Assemble with Isotropic Pair Interactions

TL;DR

This paper demonstrates that isotropic pair interactions can stabilize and enable the self-assembly of complex open crystal structures like diamond and wurtzite, traditionally thought to require directional bonds, with implications for materials science and photonics.

Contribution

The study introduces novel isotropic potentials that stabilize open lattices, challenging the belief that such structures need directional covalent interactions.

Findings

Isotropic potentials can stabilize diamond and wurtzite lattices.

Self-assembly of these structures observed in molecular dynamics simulations.

Potential applications in photonic crystal fabrication.

Abstract

Using inverse statistical-mechanical optimization techniques, we have discovered isotropic pair interaction potentials with strongly repulsive cores that cause the tetrahedrally coordinated diamond and wurtzite lattices to stabilize, as evidenced by lattice sums, phonon spectra, positive-energy defects, and self-assembly in classical molecular dynamics simulations. These results challenge conventional thinking that such open lattices can only be created via directional covalent interactions observed in nature. Thus, our discovery adds to fundamental understanding of the nature of the solid state by showing that isotropic interactions enable the self-assembly of open crystal structures with a broader range of coordination number than previously thought. Our work is important technologically because of its direct relevance generally to the science of self-assembly and specifically to photonic crystal fabrication.