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TT: Fachverband Tiefe Temperaturen

TT 18: Correlated Electrons: Low-dimensional Systems - Materials 2

TT 18.7: Vortrag

Dienstag, 26. Februar 2008, 16:45–17:00, H 2053

On the metallic conductivity of the delafossites PdCoO₂ and PtCoO₂ — •Volker Eyert^1,2, Raymond Frésard¹, and Antoine Maignan¹ — ¹Laboratoire CRISMAT, UMR CNRS-ENSICAEN(ISMRA) 6508, 6 Boulevard Maréchal Juin, 14050 Caen Cedex, France — ²Center for Electronic Correlations and Magnetism, Institut für Physik, Universität Augsburg, 86135 Augsburg, Germany

The origin of the quasi two-dimensional behavior of PdCoO₂ and PtCoO₂ is investigated by means of electronic structure calculations. They are performed using density functional theory in the local density approximation as well as the new full-potential augmented spherical wave method. We show that the electric conductivity is carried almost exclusively by the in-plane Pd (Pt) d orbitals. In contrast, the insulating O–Co–O sandwich layers of octahedrally coordinated Co atoms may be regarded as charge carrier reservoirs. This leads to a weak coupling of the Pd (Pt) layers and causes the strong anisotropy of the electric conductivity.