Wave-Like Heat Transport in Thallium Copper Selenide

In September 2026, researchers at the Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bengaluru, identified an unusual wave-like heat transport mechanism in thallium copper selenide (TlCu₅Se₃), opening possibilities for more efficient thermoelectric conversion of waste heat.

Key Points

Material Studied: TlCu₅Se₃ is a complex copper chalcogenide with a tetragonal crystal structure and open channels along the crystallographic c-axis.
Unusual Heat Transport: Strong anharmonicity and confined copper-ion dynamics allow heat to move through wave-like coherence between vibrational modes.
Ultralow Thermal Conductivity: This mechanism suppresses conventional phonon transport while maintaining structural stability.
Thermoelectric Performance: The material achieved a thermoelectric figure of merit (zT) of 1.7, among the highest reported for pristine ternary chalcogenides.
Waste Heat Recovery: Such materials could improve conversion of industrial waste heat into electricity.
Applications: Potential uses include power plants, steel and cement industries, automobiles, data centres, battery thermal management and thermal barrier coatings.