2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/221080We investigate the possibility of realizing unconventional superconductivity in doped band insulators on the square lattice and the honeycomb lattice, where the latter is found to be a good candidate due to the disconnectivity of the Fermi surface. We propose applying the theory to the superconductivity in doped layered nitride $β$-$M$NCl ($M=$Hf, Zr). Finally, we compare two groups of superconductors with disconnected Fermi surface, $β$-$M$NCl and the iron pnictides, which have high $T_c$ despite some faults against superconductivity are present.12 pages, 11 figures, in proceedings of the International Workshop on Superconductivity in Diamond and Related Materials 2008Superconductivitytext