Theory of Epitaxial Growth of Borophene on Layered Electride: Thermodynamic Stability and Kinetic Pathway

Based on first-principles calculations, we propose that the layered electride can serve as an effective substrate, in place of metal substrate, to grow borophene. We first confirm the thermodynamic stability of B@Sr₂N heterostructures by energetics analysis. Then, kinetically, we identify the atomistic pathways for a preferred 2D growth mode with a mixed triangle-hexagon configuration over 3D growth on the surface of Sr₂N, indicating the feasibility of epitaxial growth of borophene on layered electrides. As a weak metal, the significantly reduced density of states from the electride at the Fermi level helps to retain the most intrinsic electronic and transport properties of borophene, a significant advantage over metal substrate. We envision that layered electrides provide an attractive family of substrates for epitaxial growth of a range of 2D materials that can otherwise only be grown on undesirable metal substrates.