Universality of Interfacial Superconductivity in Heavily Doped Silicon

Silicon, the second most abundant element on earth, has been an ideal candidate for semiconductor industry. Recently, it was shown that a superconducting phase with a large critical temperature T-c similar to 10 K emerges locally under mesoscopic point contacts on silicon with non-superconducting metals. The superconducting phase can be realized on silicon crystals only above a threshold doping level. Here, we show that above the threshold level, the superconducting phase emerges for both electron and hole doping and the Tc remains insensitive to the type of carriers (electrons and holes). In addition, we also show that the superconducting phase can be realized on all accessible facets in commercially available silicon single crystals and tips of various elemental metals including ferromagnetic metals lead to the emergence of the superconducting phase. The insensitivity of the induced superconducting phase on the type of carriers and the crystal facets makes this phase extremely favorable candidate for applications in superconducting nano-electronics.