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

TL;DR

This paper presents a quantum-theoretical approach to engineer high-temperature superconductivity in artificial superlattices, predicting a superconducting dome by tuning nanoscale geometrical parameters and interface effects, aligning with experimental cuprate results.

Contribution

It introduces a first-principles quantum theory for designing high-Tc superconducting superlattices, emphasizing interface electric fields and quantum size effects as key factors.

Findings

Predicted superconducting Tc dome as a function of doping and geometry.

Identified the importance of the L/d ratio around 2/3 for optimal superconductivity.

Achieved agreement with experimental data on cuprate superlattices.

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