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 Tc ∼ 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.