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MM: Fachverband Metall- und Materialphysik

MM 14: Materials for Storage and Conversion of Energy IV

MM 14.3: Vortrag

Montag, 18. März 2024, 17:15–17:30, C 264

Investigation of varied doping mechanism on the thermoelectric properties of pyrite FeS₂ — •Anustup Mukherjee and Alaska Subedi — CPHT, Ecole Polytechnique. Institut Polytechnique de Paris, Palaiseau, France - 91120

Pyrite FeS₂ is an earth-abundant, nontoxic sulphide mineral with semiconducting behaviour. Hence, it has been investigated for various energy applications, including thermoelectrics using experiments and theoretical studies. Large values of thermopower have been observed at room-temperature. However, there exists a discrepancy in the magnitude and sign of thermopower reported in the literature depending on the nature of sample. Co-doped FeS₂ samples show similar variations in the magnitude of room-temperature thermopower. Therefore, it is of immense importance to examine the intrinsic thermopower of self- and Co-doped FeS₂ systems. We have investigated the electronic structure, magnetism and thermoelectric transport properties of these systems using first-principles calculations. We have implemented three different doping schemes, namely explicit Co-substitution, jellium doping and electron addition within the rigid band approximation (RBA) picture to understand electron doping in FeS₂. The former two doping schemes take structural modification and charge screening into consideration which is absent in the simpler RBA method. The thermopower is overestimated within the RBA picture, however the room-temperature thermopower observed is under 50 µV/K for all the doping schemes, suggesting that electron doped FeS₂ is not a good candidate for thermoelectric applications.

Keywords: First principles calculations; Density functional theory; Thermoelectricity; Thermopower