Ab initio design on the diamond synthesis method by core excitation

The stability of the rhombohedral graphite structure under a core excitation has been investigated by an ab initio total energy calculation based upon the density functional theory, in order to examine a possibility of the transition into the diamond structure. In the core-excited state, the graphite structure is stable. The control of the excitation energy is necessary in order to induce the transition into the diamond structure. In the valence hole state after the Auger decay process, in contrast, the graphite structure becomes remarkably unstable. The conversion into diamond from graphite can be induced even at room temperature by doped holes.