Entangled Photon Generation through Cooper Pair Recombination in a Noncentrosymmetric Quantum Well

Abstract

We explore theoretically the generation of entangled two-photon pairs by Cooper pair recombination in a noncentrosymmetric [001]-quantum well superconductor, driven by a forward-biased p-n junction with a superconducting layer which exhibits admixture Rashba and Dresselhaus spin-orbit couplings. We show that the highest achievable purity of entangled photon pairs emerges within scenarios involving pure singlet Cooper pairs, specifically, the conventional $s$-wave gap function. Our results highlight the importance of minimizing the charge-carrier level concentration and balancing the magnitudes of Rashba and Dresselhaus spin-orbit couplings to achieve entangled states with enhanced purity, which can be realized by reducing the amplitudes of antisymmetric spin-orbit couplings. In addition to purity concerns, to explore the distribution of two-photon states, we compare their population across entangled pairs for potential superconducting pairings.