Correlated nature of hybrid s -wave superconducting and Rashba lattices

Abstract

We elucidate the electronic state of a two-dimensional (2D) Rashba square lattice proximitized to a square monolayer $s$-wave superconductor, analyzing the role played by dynamical electron-electron interactions. The $\text{2D}+\text{2D}$ proximity effect induces sharp Bogoliubov and low-energy Andreev-reflected bound states, suppressing the $s$-wave gap globally. Dynamical correlations strongly renormalize the Bogoliubov quasiparticles and the Andreev levels, evolving the spin-resolved Andreev linewidths into a single bound state. We explore the channel- and spin-resolved spectral functions and analyze the reconstructed superconducting state, showing that the Rashba spin-orbit coupling drives strong channel differentiation. The mutual interplay between electron-electron and spin-orbit interactions, with proximity-induced electron pairing, lead us to introduce a generally applicable mechanism for designing Majorana fermions in 2D superconducting structures.