Lattice dynamics of thermoelectric La4Sb3

Lattice dynamics ab-initio calculations of the new thermoelectric compound La₄Sb₃ with anti- Th₄P₃ are reported. Hybridization of the lower optic mode with the acoustic modes is observed between 5.9 and 7.2 meV. As similar observations were done in other thermoelectric compounds such as skutterudites, it is suggested that this is an important effect in order to achieve low lattice thermal conductivity not only for the compounds La₄Sb₃ and La₃Te₄ with Th₄P₃ structure but also for other thermoelectric compounds, whose structures are not formed by cages.