Structural stability of carbon in the face-centered-cubic (Fm3̄m) phase Original Research Article

The structural stability of carbon in the face-centered-cubic (Fm3̄m) phase has been investigated by means of first-principles full-potential calculations. We have calculated the total energy as a function of the isotropic, tetragonal, and trigonal deformations for bulk fcc carbon. We find that the total energy shows a minimum for the isotropic deformation at the lattice parameter a=3.08 Å, but exhibits maxima for the tetragonal and trigonal deformations. This means that the fcc structure is not a true metastable phase of carbon. Possible mechanisms contributing to the stabilization of fcc carbon thin films on diamond are discussed.