The discovery of superconductivity in twisted bilayer graphene has triggered a resurgence of interest in flat-band superconductivity. Here, we investigate the square-octagon lattice, which also exhibits two perfectly flat bands when next-nearest neighbour hopping or an external magnetic field are added to the system. We calculate the superconducting phase diagram in the presence of on-site attractive interactions and find two superconducting domes, as observed in several types of unconventional superconductors. The critical temperature shows a linear dependence on the coupling constant, suggesting that superconductivity might reach high temperatures in the square-octagon lattice. Our model could be experimentally realized using photonic or ultracold atoms lattices.
@article{arxiv.2003.09243,
title = {Flat band superconductivity in the square-octagon lattice},
author = {Lizardo H. C. M. Nunes and Cristiane Morais Smith},
journal= {arXiv preprint arXiv:2003.09243},
year = {2020}
}