Quantum Transport in Boron-Doped Nanocrystalline Diamond

Highly grained thin films of boron‐doped diamond are grown by plasma‐enhanced (PE)CVD. Diamond nucleation surface treatment is discussed, together with its relation to the morphology, topology, and phase composition of the layers. The influence of the random incorporation of boron atoms in a diamond lattice is described in terms of Mott's metal and the weak localization (WL) transport mechanism. Starting from these concepts and from the experimental transport data, we build up a simple original theory of the superconductivity in boron‐doped diamond that is based on a spinflip pairing mechanism. We analyze an influence of the grain boundaries in nanocrystalline diamond (NCD) on superconductivity‐related quantum transport phenomena, and show a decisive role of the weak links created by point contacts between grains. Review: Nanocrystalline B‐doped diamond films are grown by the PE‐CVD method and the influence of doping and substrate treatments on layer composition and the diamond film topology are discussed. Starting from the randomness of boron sublattice and experimental transport data, we develop a theory of unconventional superconductivity in this material. We also show that point contacts between grains play a role of weak links affecting superconductivity and other quantum transport phenomena.