First-principle study of the AlP/Si interfacial adhesion

AlP is heterogeneous nucleation substrate of primary Si in hypereutectic Al–Si alloys, while studies on the nucleation mechanism at atomic level are absent. The pseudopotential-based DFT calculations have been carried out to investigate the atomic and electronic structure, bonding and adhesion of the AlP/Si interface. In total, eight geometries have been investigated, in which the interfacial stacking sequence is different. The favorable interfaces can be deduced for the reason that adhesive interface energies (Wad) are different, which cannot be obtained from the traditional mismatch theory. The interfacial density of states and Mulliken population are also investigated. It is found that the main bond between AlP and Si is covalent Al–Si or P–Si bond, accompanying some ionic characteristic.