Large anisotropic thermal conductivity of the intrinsically two-dimensional metallic oxide PdCoO2
Year: 2015
Type: article
Abstract: The highly conductive layered metallic oxide ${\text{PdCoO}}_{2}$ is a near-perfect analog to an alkali metal in two dimensions. It is distinguished from other two-dimensional (2D) electron systems where the Fermi surface does not reach the Brillouin zone boundary by a high planar electron density exceeding ${10}^{15}\phantom{\rule{0.28em}{0ex}}{\text{cm}}^{\ensuremath{-}2}$. 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 to 300 K 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 50 K. 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.
Source: Physical Review B
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2078785369