Year: 2004
Type: article
Abstract: We report a first-principles density-functional calculation of the electronic structure and properties of the recently discovered superconducting $\ensuremath{\beta}$-pyrochlore oxide ${\mathrm{KOs}}_{2}{\mathrm{O}}_{6}$. We find that the electronic structure near the Fermi energy ${E}_{\mathrm{F}}$ is dominated by strongly hybridized $\mathrm{Os}$ $5d$ and $\mathrm{O}$ $2p$ states. A van Hove singularity very close to ${E}_{\mathrm{F}}$ leads to a relatively large density of states at ${E}_{\mathrm{F}}$, and the Fermi surface exhibits strong nesting along several directions. These features could provide the scattering processes leading to the observed anomalous temperature dependence of the resistivity and to the rather large specific-heat mass enhancement we obtain from the calculated density of states and the observed specific-heat coefficient. An estimate of ${T}_{c}$ within the framework of the BCS theory of superconductivity taking into account the possible effects of spin fluctuations arising from nesting yields the experimental value.
Source: Physical Review B
Institutions: Northwestern University, Hiroshima University
Language: Latvian
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2102305733