Electronic Descriptors for Vacancy Formation and Hydrogen Solution in Be-Rich Intermetallics

Abstract

The use of an electronic descriptor is a high-throughput approach for predicting the chemical reactivities of various materials that has the potential to significantly facilitate the material design of Be intermetallic neutron multipliers for nuclear fusion applications. However, electronic descriptors for Be intermetallics with the desired properties, including radiation tolerance and reduced hydrogen retention, have been poorly understood. Herein, we perform first-principles calculations on 42 existing binary Be intermetallics to find an effective electronic descriptor. We demonstrate that the occupied Be p band center referenced with the Fermi level is a bulk descriptor, correlating with the Be vacancy formation energy; a positive and linear correlation with correlation factor R² = 0.85 was observed for Be₁₂X (X: transition metal). The upward shift in energy of the occupied Be p states with early or middle transition metals can reduce hydrogen solution energy, which could be attributed to the less filled anti-bonding state of interstitial hydrogen atom. It is confirmed that the bulk descriptor is an experimentally measurable scale, having the strong linearity (R² = 0.97) with the calculated; therefore, it can accelerate the material development of beryllium intermetallic neutron multipliers.

Keywords: Band theory, defects, hydrogen solution, ab-initio calculations, nuclear fusion