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.