Unusual wave-like heat transport in crystalline solid signals breakthrough converting waste heat in industries

Researchers at the Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bengaluru, have discovered an unusual wave-like heat transport regime in a copper chalcogenide material, thallium copper selenide (TlCu5Se3). The material's complex three-dimensional cloverleaf knot-like crystal framework restricts copper atom motion, generating strong lattice anharmonicity while maintaining structural stability. This confined dynamic disorder leads to wave-like phonon transport and ultralow lattice thermal conductivity, resulting in a high thermoelectric figure of merit (zT of 1.7). The finding offers a potential mechanism for converting industrial waste heat into electricity across sectors like power plants, cement industries, steel plants, automobiles, data centres, and battery thermal management.