Impact of strain-induced electronic topological transition on the thermoelectric properties of PtCoO${}_2$ and PdCoO${}_2$

Abstract

By a combination of first-principles calculations and semi-classical Boltzmann transport theory, we investigate the effect of epitaxial strain on the electronic structure and transport properties of PtCoO${}_2$ and PdCoO${}_2$. In contrast to the rather uniform elastic response of both systems, we predict for PtCoO${}_2$ a high sensitivity of the out-of-plane transport properties to strain, which is not present in PdCoO${}_2$. At ambient temperature, we identify a considerable absolute change in the thermopower from $-107\mu$V/K at $-5$\% compressive strain to $-303\mu$V/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$K for strained PtCoO${}_2$.

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Cited by in corpus (8)

• The properties of ultrapure delafossite metals
• Unconventional aspects of electronic transport in delafossite oxides
• Design of $n$- and $p$-type oxide thermoelectrics in LaNiO${}_3$/SrTiO${}_3(001)$ superlattices exploiting interface polarity
• Confinement- and strain-induced enhancement of thermoelectric properties in LaNiO${}_3$/LaAlO${}_3(001)$ superlattices
• Inducing $n$- and $p$-type thermoelectricity in oxide superlattices by strain tuning of orbital-selective transport resonances
• From basic properties to the Mott design of correlated delafossites
• Thermoelectric properties of the misfit cobaltate Ca${}_3$Co${}_4$O${}_9$
• Anomalous Hall effect in electrolytically reduced PdCoO${}_2$ thin films