thermoelectric performance

thermoelectric properties

department physics

lattice thermal

seebeck coefficient

expansion coefficient

thermoelectric power

Nature Communications

Understanding the lattice dynamics and low thermal conductivities of IV–VI, V2–VI3 and V materials is critical to the development of better thermoelectric and phase-change materials. Here we provide a link between chemical bonding and low thermal conductivity. Our first-principles calculations reveal that long-ranged interaction along the 〈100〉 direction of the rocksalt structure exist in lead chalcogenides, SnTe, Bi2Te3, Bi and Sb due to the resonant bonding that is common to all of them. This long-ranged interaction in lead chalcogenides and SnTe cause optical phonon softening, strong anharmonic scattering and large phase space for three-phonon scattering processes, which explain why rocksalt IV–VI compounds have much lower thermal conductivities than zincblende III–V compounds. The new insights on the relationship between resonant bonding and low thermal conductivity will help in the development of better thermoelectric and phase change materials. Understanding the link between thermal conductivity and chemical bonding is important for the development of thermoelectric and phase-change materials. Here, the authors associate the low thermal conductivity of IV–VI materials with near-ferroelectric behaviour from their resonant bonding.

Resonant bonding leads to low lattice thermal conductivity