Tunneling Spectroscopy and Vortex Imaging in Boron-Doped Diamond
  We present the first scanning tunneling spectroscopy study of single-crystalline boron doped diamond. The measurements were performed below 100 mK with a low temperature scanning tunneling microscope. The tunneling density of states displays a clear superconducting gap. The temperature evolution of the order parameter follows the weak coupling BCS law with $\Delta(0)/k_B T_c \simeq 1.74$. Vortex imaging at low magnetic field also reveals localized states inside the vortex core that are unexpected for such a dirty superconductor. 
B. Sacepe, C. Chapelier, C. Marcenat, J. Kacmarcik, T. Klein, M.   Bernard, E. Bustarret