Work

Impact of strain-induced electronic topological transition on the thermoelectric properties of PtCoO2 and PdCoO2

Year: 2015

Type: article

Abstract: By a combination of first-principles calculations and semiclassical Boltzmann transport theory, we investigate the effect of epitaxial strain on the electronic structure and transport properties of ${\mathrm{PtCoO}}_{2}$ and ${\mathrm{PdCoO}}_{2}$. In contrast to the rather uniform elastic response of both systems, we predict for ${\mathrm{PtCoO}}_{2}$ a high sensitivity of the out-of-plane transport properties to strain, which is not present in ${\mathrm{PdCoO}}_{2}$. At ambient temperature we identify a considerable absolute change in the thermopower from $\ensuremath{-}107\phantom{\rule{0.222222em}{0ex}}\ensuremath{\mu}\mathrm{V}/\mathrm{K}$ at $\ensuremath{-}5%$ compressive strain to $\ensuremath{-}303\phantom{\rule{0.222222em}{0ex}}\ensuremath{\mu}\mathrm{V}/\mathrm{K}$ at $+5%$ tensile strain. This remarkable response is related to distinct changes of the Fermi surface, which involve the crossing of two additional bands at a moderate compressive in-plane strain. Combining our transport results with available experimental data on electrical and lattice thermal conductivity we predict a thermoelectric figure of merit of up to $ZT=0.25$ at $T=600$ K for strained ${\mathrm{PtCoO}}_{2}$.

Source: Physical Review B

DOI: 10.1103/physrevb.92.235140

Authors: Markus Ernst Gruner, Ulrich Eckern, Rossitza Pentcheva

Institutions: University of Duisburg-Essen, Technical University of Munich, University of Augsburg

Language: English

Topic: Advanced Thermoelectric Materials and Devices

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: bronze

Funder: Deutsche Forschungsgemeinschaft

Award: G580818053