Large anisotropic thermal conductivity of intrinsically two-dimensional metallic oxide PdCoO${}_2$

Abstract

The highly conductive layered metallic oxide \pdcoo{} is a near-perfect analogue to an alkali metal in two dimensions. It is distinguished from other two-dimensional electron systems where the Fermi surface does not reach the Brillouin zone boundary by a high planar electron density exceeding $10^{15}$ cm${}^{-2}$. The simple single-band quasi-2D electronic structure results in strongly anisotropic transport properties and limits the effectiveness of electron-phonon scattering. Measurements on single crystals in the temperature range from 10-300K show that the thermal conductivity is much more weakly anisotropic than the electrical resistivity, as a result of significant phonon heat transport. The in-plane thermoelectric power is linear in temperature at 300\,K and displays a purity-dependent peak around 50K. Given the extreme simplicity of the band-structure, it is possible to identify this peak with phonon drag driven by normal electron-phonon scattering processes.

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References in corpus (4)

• Topological Surface States Protected From Backscattering by Chiral Spin Texture
• On the thermoelectricity of correlated electrons in the zero-temperature limit
• Scaling behavior in thermoelectric misfit cobalt oxides
• On the metallic conductivity of the delafossites PdCoO2 and PtCoO2

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• Finite-size effects of electron transport in PdCoO${}_2$
• A 3D Tight-Binding Model for La-Based Cuprate Superconductors
• Effective reduction of PdCoO2 thin films via hydrogenation and sign tunable anomalous Hall effect
• Fully two-dimensional incommensurate charge modulation on the Pd-terminated polar surface of PdCoO2
• Anisotropic Seebeck coefficient of ${\mathrm{Sr}}_2\mathrm{Ru}{\mathrm{O}}_4$ in the incoherent regime
• Anomalous Hall effect in electrolytically reduced PdCoO${}_2$ thin films
• Disorder-enhanced effective masses and deviations from Matthiessen's rule in PdCoO${}_2$ thin films