“…Recent advances in artificial intelligence (AI) techniques have significantly accelerated the discovery of materials with optimal properties for various applications, including superconductivity, catalysis, and thermoelectricity. [19][20][21][22] In our recent high-throughput prediction of the phonon transport properties of large-scale inorganic crystals based on deep learning, 22,23 after thoroughly screening 80 000 cubic crystals from the Open Quantum Materials Database (OQMD), 24,25 two metallic compounds, namely PbAuGa and CsKNa, are identified with anomalously low phononic thermal conductivity, having the lowest phononic thermal conductivity among all crystalline materials we have known so far. Obviously, the phononic thermal conductivity of metallic PbAuGa and CsKNa is well below the reasonable range.…”