Chemistry and Physics Faculty Proceedings, Presentations, Speeches, Lectures


Search for Superconductivity in Doped Carbon Allotropes

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11th International Conference on Materials and Mechanisms of Superconductivity, Geneva, Switzerland, August 23-28, 2015

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There have been significant studies to induce superconductivity and increase transition temperatures (Tc) in the varying allotropes of carbon. Doping of diamond films with boron = 0.5–5 Vol% achieved Tc up to 7K, and superconductivity was in Cs2RbC60 compounds with Tc of 33 K at atmosphere pressure. However, so far Tc > 20K has not been achieved in carbon made into the form of a wire conductor carrying significant supercurrent densities. Herein we report on attempt to achieve a high Tc measured resistively in different carbon allotropes with potential for wires, including amorphous carbon, diamond, graphite thin films, carbon fibers doped with promising elements including B, P, S and other. Carbon films were prepared by pulsed laser deposition (PLD) with doped or un-doped single-targets. Ion implantation was also used to add gaseous dopants very difficult to incorporate by PLD. Ion implantation energies and dosing times were varied to achieve different doping depths and profiles. Initial results with P implantation show a dramatic decrease of resistivity by a factor of 105 at T < 50K, with the carbon film changing from semiconducting to metallic.