Real-space d-wave superconductivity from weak attraction

TL;DR

This paper demonstrates that weak out-of-plane attraction can induce real-space d-wave pairs in a tetragonal lattice, providing insights into cuprate superconductivity and supporting a real-space pairing mechanism.

Contribution

It shows that even weak attraction can produce d-wave pairs in a 3D lattice, advancing understanding of superconductivity in cuprates.

Findings

Weak attraction induces real-space pairs with d symmetry

Supports real-space mechanism of cuprate superconductivity

Provides rules for real-space superconductivity

Abstract

It is shown that even a weak out-of-plane attraction, V -> 0, can form real-space pairs in the body-centered tetragonal lattice despite the presence of a Hubbard repulsion and a fully developed three-dimensional kinetic energy. In the hole channel, the pairs have d orbital symmetry which, following Bolgoliubov's argument, translates into a d-symmetric macroscopic superconducting order parameter. The findings help us to understand key features of La_{2-x}Sr_xCuO_4 and further support the real-space mechanism of superconductivity in cuprates. The rules of real-space superconductivity are formulated at the end.