Single-orbital realization of high-temperature $s^\pm$ superconductivity in the square-octagon lattice

TL;DR

This paper predicts high-temperature $s^\uparrow ext{±}$-wave superconductivity in a single-orbital Hubbard model on the square-octagon lattice, proposing octagraphene as a potential material with superconducting properties comparable to cuprates.

Contribution

It introduces a new lattice model for high-temperature superconductivity and suggests a real material realization, octagraphene, with similar pairing strength to cuprates.

Findings

Consistent $s^\uparrow ext{±}$ pairing symmetry across different methods.

Realistic coupling strength yields pairing comparable to cuprates.

Proposes octagraphene as a candidate material for high-temperature superconductivity.

Abstract

We propose possible high-temperature superconductivity (SC) with singlet $s^\pm$-wave pairing symmetry in the single-orbital Hubbard model on the square-octagon lattice with only nearest-neighbor hopping terms. Three different approaches are engaged to treat with the interacting model for different coupling strengths, which yield consistent result for the $s^\pm$ pairing symmetry. We propose octagraphene, i.e., a monolayer of carbon atoms arranged into this lattice, as a possible material realization of this model. Our variational Monte Carlo study for the material with realistic coupling strength yields a pairing strength comparable with the cuprates, implying a similar superconducting critical temperature between the two families. This study also applies to other materials with similar lattice structure.