Designed Diamond Ground State via Optimized Isotropic Monotonic Pair Potentials

TL;DR

This paper develops optimized isotropic pair potentials that reliably produce diamond crystal structures as their ground state across various pressures, using inverse statistical-mechanical methods and stability constraints.

Contribution

It introduces a novel inverse design approach to create simple isotropic potentials that stabilize diamond structures over a wide pressure range.

Findings

Optimized potentials successfully produce diamond ground states.

Diamond structures are robustly obtained from disordered configurations.

The phase diagram reveals other crystal structures at different pressures.

Abstract

We apply inverse statistical-mechanical methods to find a simple family of optimized isotropic, monotonic pair potentials, under certain constraints, whose ground states for a wide range of pressures is the diamond crystal. These constraints include desirable phonon spectra and the widest possible pressure range for stability. We also ascertain the ground-state phase diagram for a specific optimized potential to show that other crystal structures arise for other pressures. Cooling disordered configurations interacting with our optimized potential to absolute zero frequently leads to the desired diamond crystal ground state, revealing that the capture basin for the global energy minimum is large and broad relative to the local energy minima basins.