Towards electric-field-induced superconductivity in ion-gated diamond surfaces

In this Invited Talk, I will summarize the main results in the literature and discuss the work which has been carried out in our group in order to reach the predicted field-induced superconducting state at the surface of ion-gated diamond. Since ionic gating alone has been shown to be insufficient to induce the required values of charge-carrier density, we attempted a co-doping approach where EDL transistors were fabricated on different boron-doped diamond surfaces. In this approach, the boron dopants play a dual role: On the one hand, they provide an intrinsic hole density in the system which is larger than that obtained by pure hydrogen termination, thus reducing the induced hole density one has to provide with the ionic gate to drive the 2-dimensional hole gas into the SC phase. On the other hand, by improving the metallicity of the system, they can potentially increase the capacitance of the electric doubel layer and increase the maximum attainable values of hole density.