Superconductivity in silicon: a review

Silicon, one of the most abundant elements found on Earth, has been an excellent choice of the semiconductor industry for ages. Despite it's remarkable applications in modern semiconductor-based electronic devices, the potential of cubic silicon in superconducting electronics remained a challenge because even heavily doped silicon crystals do not superconduct under normal conditions. It is apparent that if superconductivity can be introduced in cubic silicon, that will bring a breakthrough in low-dissipation electronic circuitry. Motivated by this, attempts have been made by several research groups to induce superconductivity in silicon through a number of different routes. Some of the other structural phases of silicon like $\beta$-Sn and simple hexagonal are, however, known to display superconductivity. In the present review article, various theoretical and experimental aspects of superconductivity in silicon are discussed. Superconductivity in different phases and different structural forms of silicon are also reviewed. We also highlight the potential of superconducting phases of silicon for technological applications in super-conducting nano-electronics.