Effect of B-complexes on lattice structure and electronic properties in heavily boron-doped diamond

On the basis of first-principle calculations for a series of B-doped supercells models, we confirmed that the lattice parameter increases with the boron concentration in a proximity linear relation. The electronic structure shows that the impurity band induced by B-complexes except B dimer mixes with valence band and the Fermi level locates in the valence band in heavily boron-doped diamond, which may well explain recent superconducting transition experimental findings. Our results indicate that the superconducting critical temperature T_C is not only related to the B concentration, but also affected by the B configurations in diamond lattice. © 2007 Elsevier B.V. All rights reserved.