  Candidates for new thermoelectric and superconducting materials, which have
narrow band gap and flat bands near band edges, were searched by the
high-throughput first-principles calculation from an inorganic materials
database. The synthesized SnBi$_2$Se$_4$ among the target compounds showed a
narrow band gap of 354 meV, and a thermal conductivity of 1 W/Km at ambient
pressure. The sample SnBi$_2$Se$_4$ showed a metal-insulator transition at 11.1
GPa, as predicted by a theoretical estimation. Furthermore, the two
pressure-induced superconducting transitions were discovered at under 20.2 GPa
and 47.3 GPa. The data-driven search is a promising approach to discover new
functional materials.
