Field-effect–induced superconductivity in surfaces of tetrahedrally coordinated semiconductors: The case of (111) hydrogenated silicon

We show the possibility of inducing a superconductive phase transition in tetrahedrally coordinated semiconductors via field-effect (FET) doping by taking as an example the hydrogenated (111) silicon surface. We perform density functional theory computations of the electronic and vibrational properties of the system in the proper FET geometry, by taking into account the applied electric field and the induced charge density. Using a simplified superconductive model at q = Γ and the McMillan/Allen-Dynes formula, we get an estimate of the super- conductive critical temperature. We observe that, by heavily doping with holes at ndop = 6·1014 cm−2, we get an electron-phonon coupling constant of λ_Si = 0.98 and a superconductive phase transition at Tc ∈ [8.94; 10.91] K, with μ∗ ∈ [0.08; 0.12].