32 Ages of the universe in just 2 weeks: High-speed Shock-waves in DFT

To date, the ab initio exploration of materials in extreme conditions has focused on equilibrium studies. However, this fails to capture the dynamic effects commonly seen in the shock-waves used to reach extreme conditions experimentally. In order to more accurately reproduce these mechanisms, we have developed a partially fire-and-forget approach to induce a series of independent shocks into the medium, to determine the shock response of the material.

We have also used optimisations of the Hugoniostat[1] approach tailored to ab initio calculation, so that we can use DFT-based methods to accurately calculate a complete Hugoniot in a single calculation. Using the series of isolated shocks and a predictor algorithm to approach the target pressure in uniform steps. From this, we can extract an ideal coupling parameter, reducing the calculation time, even for extreme compressions.

These two distinct improvements make it feasible to perform ab initio shock studies with high accuracy in DFT. We demonstrate these capabilities with simulations of shocks in quartz.

[1] Jean-Bernard Maillet and Stéphane Bernard. Uniaxial hugoniostat: Method and applications. In Shock Compression of Condensed Matter. American Institute of Physics, 2001