Absence of superconductivity in boron-implanted diamond

Recently, superconductivity has been found in heavily boron-doped diamond prepared by high temperature/high pressure synthesis or chemical vapour deposition. An alternative doping method of technological relevance is ion implantation. It is an open question whether superconductivity can also be obtained in boron-implanted diamond. Here we report on the transport and magnetic properties of high dose (2.3 × 10 16–1.7 × 10 17 cm − 2 ) boron-implanted natural IIa diamond samples doped at elevated temperature of 900 °C and subsequently annealed at 1500 °C and 1700 °C. For comparison implantation at room temperature was also carried out. The samples were further characterized by Raman and infrared spectroscopy. No superconductivity could be detected in the samples at temperatures down to 40 mK. We discuss the possible origin for the absence of superconductivity.