Structural and thermoelectric properties ofFeSb3skutterudite thin films

Abstract

Skutterudites are promising materials for future thermoelectric applications. Whereas the skutterudite CoSb 3 is intensively studied, nearly no investigations for FeSb 3 are performed due to its metastable character and the comparably low decomposition temperature.In this work, single phase FeSb 3 thin films were prepared by co-deposition of Fe and Sb using molecular beam epitaxy at room temperature followed by post-annealing. The transport properties of a Fe-Sb composition series were determined and reveal high power factors S 2 σ up to 14 µW/K 2 cm. Furthermore, the structural parameters, the electronic structure and the transport parameters were calculated by density functional theory giving excellent agreement to the experimental data.

Thermoelectric properties of the unfilled skutteruditeFeSb3from first principles and Seebeck local probes

“…4 and 5 are larger and close to the experiments in Ref. 4. The iron keep their initial positions, whereas the antimony atoms move slightly along the y and z directions.…”

“…4 predicted a fully metallic state for the non spin-polarized configuration, as we do in the hybrid functional formalism. Råsander et al find the same metallic behavior but further show the configuration to be dynamically unstable, which renders its use in Ref.…”

“…Råsander et al find the same metallic behavior but further show the configuration to be dynamically unstable, which renders its use in Ref. 4 questionable. We show below that all of the properties (magnetism, semiconducting behavior, and transport) can be explained with the AFM-G model.…”

“…In Ref. 4, DFT calculations were performed with the LDA, the PBE and the PW91 functional, in the non spin-polarized case and in the spin-polarized case as well. However, they focused on the non spin-polarized case, which is instable 5 , and our hybrid functional results are in agreement with this observation.…”

“…The full substitution results in unfilled FeSb 3 , our compound of interest. While FeSb 3 has not yet been synthesized in bulk, thick films have been grown and studied [2][3][4] . Experiments suggest a semiconducting compound with a small gap, which is paramagnetic at least down to 10 K. There are some variations in the lattice constant between studies, and also carrier densities as we will show below.…”