  The design of uranium-based thermoelectric materials presents a novel and
intriguing strategy for directly converting nuclear heat into electrical power.
Using high-level first-principles approach combined with accurate solution of
Boltzmann transport equation, we demonstrate that a giant n-type power factor
of 13.8 mW/mK^2 and a peak ZT value of 2.2 can be realized in the heavy-fermion
UN2 compound at 700 K. Such promising thermoelectric performance arises from
the large degeneracy (Nv=14) of heavy conduction band coupled with weak
electron-phonon interactions, which is in principle governed by the strong
Coulomb correlation among the partially filled U-5f electrons in the
face-centered cubic structure. Collectively, our theoretical work suggests that
the energetic UN2 is an excellent alternative to efficient radioisotope power
conversion, which also uncovers an underexplored area for thermoelectric
research.
