Low-temperature enhanced figure of merit of ThSixP1-x and prospects for thermoelectric energy performance

Rare Earth metals and actinides-based materials gained immense attention of scientists and technologists owing to their fascinating fundamental and applied prospects. These are large density, neutron abundance, enhanced melting temperature and thermal stability which enhance their thermal performance. Herein, we report on the low temperature-enhanced thermoelectric performance of ThP through silicon substitution via ThSixP1-x (x= 0, 0.25, 0.5, 0.75, 1). For the density functional theory-based quantum computation analysis on the Si substitution-assisted properties of ThP, we utilize all-electron full-potential with linearized augmented plane wave. For the theoretical characterization of the compounds for the desired properties, we treat the exchange-correlation density functional within TB-mBJ approximation. The computed thermoelectric properties via Boltzmann theory as implemented in BoltzTrap computer code are Seebeck coefficient (S), electrical (sigma) and thermal conductivity (k), power factor (PF) (S-2 sigma), and figure ofmerit (ZT). The substitution of Si into ThP renders a considerable enhancement of thermoelectric and transport performance of the ThSixP1-x samples with enhanced s, PF, and ZT of orders 3.0 x 10(20) (Omega.s.cm)(-1), 2.5 x 10(12) Wm(-1)K(-2)s(-1) and 1.6 at 50 K, respectively. To our knowledge, this is the highest low-temperature thermal efficiency achieved for the metallic thorium silicides. As such, the reported results hold great promise for fundamental prospects and technological interest such as thermoelectricity and fertile materials as nuclear fuel for clean nuclear energy technology.