Impact of hole-doping on the thermoelectric properties of pyrite FeS2

Abstract

We present a comprehensive first-principles analysis of the thermoelectric transport properties of hole-doped pyrite FeS${}_2$ that includes electron-phonon interactions. This work was motivated by the observed variations in the magnitude of thermopower reported in previous experimental and theoretical studies of hole-doped FeS${}_2$ systems. Our calculations reveal that hole-doped FeS${}_2$ exhibits large positive room-temperature thermopower across all doping levels, with a room-temperature thermopower of 608 $\mu$V/K at a low hole-doping concentration of 10${}^{19}$ cm${}^{-3}$. This promising thermopower finding prompted a comprehensive investigation of other key thermoelectric parameters governing the thermoelectric figure of merit $ZT$. The calculated electrical conductivity is modest and remains below 10${}^5$ S/m at room-temperature for all doping levels, limiting the achievable power factor. Furthermore, the thermal conductivity is found to be phonon driven, with a high room-temperature lattice thermal conductivity of 40.5 W/mK. Consequently, the calculated $ZT$ remains below 0.1, suggesting that hole-doped FeS${}_2$ may not a viable candidate for effective thermoelectric applications despite its promising thermopower.

8 pages, 10 figures, 1 table, 6 equations

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