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Thermopower Enhancement from Engineering the Na0.7CoO2 Interacting Fermiology via Fe Doping

: Richter, R.; Shopova, D.; Xie, W.; Weidenkaff, A.; Lechermann, F.

Volltext ()

Advances in condensed matter physics 2018 (2018), Art. 9725321, 7 S.
ISSN: 1687-8124
ISSN: 1687-8108
Zeitschriftenaufsatz, Elektronische Publikation
Fraunhofer IWKS ()

The sodium cobaltate system NaxCoO2 is a prominent representant of strongly correlated materials with promising thermoelectric response. In a combined theoretical and experimental study we show that, by doping the Co site of the compound at x=0.7 with iron, a further increase of the Seebeck coefficient is achieved. The Fe defects give rise to effective hole doping in the high-thermopower region of larger sodium content x. Originally filled hole pockets in the angular-resolved spectral function of the material shift to low energy when introducing Fe, leading to a multisheet interacting Fermi surface. Because of the higher sensitivity of correlated materials to doping, introducing adequate substitutional defects is thus a promising route to manipulate their thermopower.