superconductors (Type II)

Many additional elements can be coaxed into a superconductive state with the application of high pressure. These are called Type II semiconductors. (Note: normally configured bulk carbon (amorphous, diamond, graphite, white) will not superconduct at any temperature. However, a critical transition temperatyre (Tc) of 15K has been reported for elemental carbon when the atoms are configured as highly-aligned, single-walled nanotubes. Nanotubes made from other materials, like silicon, boron-nitride or tungsten-disulfide, may also exhibit superconductivity. Since the penetration depth is much larger than the coherence length, nanotubes are characterized as "Type II" superconductors.