Structures of GaN(0001)-(2x2), -(4x4), and -(5x5) surface reconstructions

Molecular-dynamics simulation employing Tersoff and Ito-Kohr-Das Sarma potentials has been performed to study structural properties of Al/SiC interfaces. The atomic configuration and cohesive energy of various Al/SiC interfaces formed between low-index planes of Al and SiC surfaces have been calculated. A positive correlation between the existence of a specific orientation relationship (OR) and its cohesive energy has been identified and used as a guide in search of more Al/SiC OR's. Structural disorder is induced by the interfacial bonding dominated by the Al-C interaction, but is limited to a narrow region near the interface, thus maintaining definite OR's between Al and SiC. It is shown that the cohesive energy decreases only slightly when the OR's deviate from the ideal arrangement within a small range,,suggesting the stability of these nonideal OR's. The calculated results are in good agreement with experiment and provide an atomic-level description for the low-index Al/SiC interfaces. [S0163-1829(99)10115-2].