First-Principles Calculations on Electronic Structure, Adhesion Strength, and Interfacial Stability of Mg(0001)/AlB2(0001) Nucleation Interface

In this work, Mg(0001)/AlB₂(0001) interfaces with various terminations and stacking orders were constructed, and the atomic and electronic structures and adhesion work (W_ad) of the interface were investigated using the first-principles calculations. Notably, during the geometry optimization process, the B-mid-top (B-MT) Mg(0001)/AlB₂(0001) interface exhibits the most significant interface changes and manifests the least stability. Horizontal movement of Mg atoms in the first layer of the Mg surface slab, along the normal direction, results in a structure akin to the structurally optimized hexagonal close-packed (HCP) interface. The B-HCP interface demonstrates the highest stability, the largest ideal W_ad, and the smallest interface distance. The interface enhances the binding strength of the Mg-side sub-interface, but diminishes the binding strength of the AlB₂-side sub-interface. Furthermore, Mg atoms can form metallic/covalent mixed bonds with Al atoms on the Al-terminal AlB₂ surface and form ionic bonds with B atoms on the B-terminal AlB₂ surface. Mg(0001)/AlB₂(0001) interface has good bonding properties. This research provides strong theoretical support for an in-depth understanding of Mg/AlB₂ interface characteristics.