Hybridization-induced superconductivity from the electron repulsion on a tetramer lattice having a disconnected Fermi surface

TL;DR

This paper demonstrates that a tetramer lattice with disconnected Fermi surfaces can exhibit high-temperature superconductivity driven by electron repulsion, due to unique pairing mechanisms across hybridized molecular orbitals.

Contribution

It reveals a novel mechanism for superconductivity in a tetramer lattice with disconnected Fermi surfaces, emphasizing the role of intra-unit cell structure and hybridized orbitals.

Findings

High T_c achieved in a tetramer lattice with disconnected Fermi surface

Superconductivity mediated by electron repulsion and spin fluctuations

Nodal structure dominated by intra-unit cell hybridization

Abstract

Plaquette lattices with each unit cell containing multiple atoms are good candidates for disconnected Fermi surfaces, which are shown by Kuroki and Arita to be favorable for spin-flucutation mediated superconductivity from electron repulsion. Here we find an interesting example in a tetramer lattice where the structure within each unit cell dominates the nodal structure of the gap function. We trace its reason to the way in which a Cooper pair is formed across the hybridized molecular orbitals, where we still end up with a T_c much higher than usual.