Anti-bonding mediated record low and comparable-to-air lattice thermal conductivity of two metallic crystals

Abstract

PbAuGa and CsKNa possess record low lattice thermal conductivity which is even comparable to that of air. The loosely bonded Au and Cs atoms in PbAuGa and CsKNa respectively act as intrinsic rattlers and thus induce strong phonon anharmonicity.