First-principles calculation on LaAlO3 as the heterogeneous nucleus of TiC

Abstract

In this work, the interface atomic structure, bonding character, adhesion work and interfacial energy of LaAlO3 (100)/TiC (100) interface were studied and the effectiveness of the LaAlO3 as the heterogeneous nucleus of TiC was analyzed using a first-principles density functional plane-wave ultrasoft pseudopotential method. The results indicate that, the surface energy of TiC (100) surface stabilizes gradually with increase of the slab thickness, and it converges to 2.18J/m2 ultimately. LaAlO3 (100) surface contains two terminated structures, which are LaO-terminated one and AlO2-terminated one. When La chemical potential (ΔμLa) is small, surface stability of AlO2-terminated structure is larger than that of LaO-terminated one. With the increase of ΔμLa, surface stability of AlO2-terminated structure decreases while that of LaO-terminated one increases gradually. For the two LaAlO3 (100)/TiC (100) interfaces, the adhesion work of LaO-terminated structure is larger than that of AlO2-terminated one while the interface distance of LaO-terminated structure is smaller than that of AlO2-terminated one, which indicates that the LaO-terminated structure is more stable than the AlO2-terminated one. When ΔμLa is in the range of −14.59eV to −14.21eV (−4.11eV to −3.74eV), the interfacial energy of LaAlO3 (100)/TiC (100) interface with AlO2-terminated structure (LaO-terminated structure) is in the range of 0–0.204J/m2, which meets the requirements of LaAlO3 (100)/TiC (100) interface as the heterogeneous nucleation one.