Berlin 2015 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 36: Poster Session I
DS 36.83: Poster
Donnerstag, 19. März 2015, 09:30–12:00, Poster A
Tuning the thermoelectric properties of cobaltates by epitaxial strain — •Markus Ernst Gruner1,2 and Rossitza Pentcheva2,1 — 1Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II), Technische Universität München, Lichtenbergstraße 1, 85748 Garching, Germany — 2Faculty of Physics and Center for Nanointegration, CENIDE, University of Duisburg-Essen, Lotharstr. 1, 47048 Duisburg, Germany
The hexagonal delafossites PdCoO2 and PtCoO2 exhibit
highly anisotropic transport properties and have been identified as
potential themoelectric materials.
For instance, along the hexagonal a-b-plane the thermopower Sxx exhibits positive values characterisitic of a
regular metal, while negative values Szz are encountered in
direction of the c-axis, with a much higher absolute value [1].
By means of density functional theory calculations
in connection with Boltzmann transport theory
we investigate the effect of epitaxial strain
on the thermoelectric properties. We find that for PdCoO2 the
anisotropic properties of conductivity and thermopower are essentially
maintained under in-plane strain.
Moreover, a 30% variation of Szz is found in the considered strain
regime. The transport results are related to the
specific properties of electronic structure and Fermi surface.
Funding by the DFG (SFB/TR80, project G8) is gratefully acknowledged.
[1] K. P. Ong, D. J. Singh, P. Wu, Phys. Rev. Lett. 104, 176601 (2014).