Electronic structure of theC(111)surface: Solution by self-consistent many-body calculations

Abstract

We present a first-principles calculation of the geometry and of the electronic structure for the C1112 1 surface. We find that this surface reconstructs with -bonded chains without any significant dimerization or buckling. At the DFT level, it appears semimetallic, in agreement with previous calculations, but in contrast to experimental evidence. Even the introduction of quasi-particle corrections within the usual GW scheme does not lead to the opening of the gap between surface states. Quasiparticle corrections to the surface band structure are hence calculated within a self-consistent GW scheme. A gap of about 1 eV is found between the surface states, thus finally solving the discrepancy between theory and experiment. The 111 face is the cleavage surface of diamond. Understanding its behavior is important from a technological point of view, the 111 plane is one of the growth surfaces for the chemical vapor deposition CVD of diamond, and from a theoretical point of view, in order to elucidate the principles of surface reconstructions in the other group IV semiconductors. Many potential applications of diamond arise from specific properties of its surfaces: while its negative electron affinity and unique surface conductivity make it attractive for electronic and optoelectronic devices, 1 its extreme surface chemical inertness makes it a good candidate for biomedical applications reducing the chances of rejection; moreover, boron-doped diamond electrodes have been used in water purification and in the detection of many substances, espe