First-principles calculations of zinc-blende GeC(0 0 1) surfaces

We report the structural parameters, electronic and chemical bonding properties of zinc-blende GeC(0 0 1) surfaces investigated using the plane-wave ultrasoft pseudopotential technique based on density-functional theory (DFT). Both Ge- and C-terminated relaxed structures of two slabs have been analyzed and it can be concluded that the C atoms relax inward while Ge atoms relax outward. The electronic band structures and density of states of two slabs have been discussed, showing a metallic surface properties accompanied with overlaps of valence and conduction bands for Ge-terminated surface and a P-type semiconductor property with a direct band gap of 0.6 eV for C-terminated surface. The surface energy and stability have been calculated, which indicates Ge-terminated slab surface is more stable than C-terminated surface.