High-Tc superconducting dome in artificial heterostructures made of nanoscale quantum building blocks

Abstract

While the search of high Tc superconductivity was driven mostly by trial and error methodology searching for novel materials, here we provide a quasi-first-principle quantum theory for engineering superconductivity in artificial high-Tc superlattices (AHTS) with period d, ranging from 5.28 down to 3 nanometers, made of superconducting quantum wells of variable thickness L. An important feature of our quantum design is the key role of the interface internal electric field giving Rashba spin-orbit coupling (SOC) in the nanoscale quantum superconducting building blocks. By tuning the geometrical conformational parameter L/d around its magic ratio 2/3 we predict the superconducting dome of Tc versus doping characteristic of unconventional superconductors. Quantum size effects, controlled by L/d, change the energy width and splitting of two quantum subbands formed by the electronic space charge confined in superconducting nano-layers. The theoretical superconducting dome Tc versus charge density controlled by the Fano-Feshbach resonance between two superconducting gaps has been able to predict experimental results on cuprate AHTS by tuning the geometry of superlattices of quantum wells made of superconducting layers (S) of thickness L of modulation doped stoichiometric Mott insulator La2CuO4 with no chemical dopants, with interface space charge confined within normal metal (N) overdoped cuprate layers