Unraveling the unusually high electrical conductivity of the delafossite metal PdCoO${}_2$

Abstract

The prototypical delafossite metal PdCoO${}_2$ has been the subject of intense interest for hosting exotic transport properties. Using first-principles transport calculations and theoretical modeling, we reveal that the high electrical conductivity of PdCoO${}_2$ at room temperature originates from the contributions of both high Fermi velocities, enabled by Pd $4d_{z^2}-5s$ hybridization, and exceptionally weak electron-phonon coupling, which leads to a coupling strength ($\lambda =0.057$) that is nearly an order of magnitude smaller than those of common metals. The abnormally weak electron-phonon coupling in PdCoO${}_2$ results from a low electronic density of states at the Fermi level, as well as the large and strongly facetted Fermi surface with suppressed Umklapp electron-phonon matrix elements. We anticipate that our work will inform the design of unconventional metals with superior transport properties.

6 pages, 3 figures

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• Advanced capabilities for materials modelling with Quantum ESPRESSO
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• On the metallic conductivity of the delafossites PdCoO2 and PtCoO2
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Cited by in corpus (1)

• Dichotomy of electron-phonon interactions in the delafossite PdCoO${}_2$: From weak bulk to polaronic surface coupling