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Using molecular beam epitaxy techniques, we demonstrate the growth of thin-film Fe2VAl with a stoichiometric chemical composition. Even for a low-temperature-grown Fe2VAl film, the electrical properties are similar to those of bulk Fe2VAl reported previously. We note that the Seebeck coefficient (S) is slightly larger (∼40 µV/K) and the thermal conductivity (κ) is smaller [∼7.5 W/(m·K)] than those of bulk Fe2VAl [S = 30 µV/K, κ = 25 W/(m·K)]. This study shows that thermoelectric Fe2VAl films with relatively high performance compared to bulk Fe2VAl can be developed for potential applications.

Managing heat dissipation is a necessity for nanoscale electronic devices with high-density interfaces, but despite considerable effort, it has been difficult to establish the phonon transport physics at the interface due to a “complex” interface layer. In contrast, the amorphous/epitaxial interface is expected to have almost no “complex” interface layer due to the lack of lattice mismatch strain and less associated defects. Here, we experimentally observe the extremely-small interface thermal resistance per unit area at the interface of the amorphous-germanium sulfide/epitaxial-lead telluride superlattice (~0.8 ± 4.0 × 10‒9 m2KW−1). Ab initio lattice dynamics calculations demonstrate that high phonon transmission through this interface can be predicted, like electron transport physics, from large vibron-phonon density-of-states overlapping and phonon group velocity similarity between propagon in amorphous layer and “conventional” phonon in crystal. This indicates that controlling phonon (or vibron) density-of-states and phonon group velocity similarity can be a comprehensive guideline to manage heat conduction in nanoscale systems.

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