Does the orbital degeneracy play any role in the high thermopower of lamellar cobaltites?

Michaël Pollet (1) , Jean-Pierre Doumerc (1) , Emmanuel Guilmeau (2) , Dominique Grebille (2) , Jean-François Fagnard (3) , Rudi Cloots (4)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
2 CRISMAT - Laboratoire de cristallographie et sciences des matériaux
3 Institut Montefiore - Department of Electrical Engineering and Computer Science
4 Laboratory of Structural Inorganic Chemistry, Chemistry Department B6

This article investigates the role of the CoO6 octahedron distortion on the electronic properties and more particularly on the high value of the Seebeck coefficient in the BiCaCoO lamellar cobaltites. Our measurements provide clues indicating that the t2g orbital degeneracy lifting has to be considered to account for the observed high temperature limit of the thermopower...

Mots clés: Thermoelectricity; Cobaltites; Electronic properties; Crystal field; Electronic correlations

Domaines: Matériaux

Michaël Pollet, Jean-Pierre Doumerc, Emmanuel Guilmeau, Dominique Grebille, Jean-François Fagnard, et al.. Does the orbital degeneracy play any role in the high thermopower of lamellar cobaltites?. Journal of Applied Physics, 2007, 101 (8), pp.083708. ⟨10.1063/1.2717602⟩. ⟨hal-00156840⟩