Physics – Condensed Matter – Superconductivity
Scientific paper
2006-02-24
Phys. Rev. B 73, 094518 (2006) [http://link.aps.org/abstract/PRB/v73/e094518]
Physics
Condensed Matter
Superconductivity
Accepted for publication in PRB
Scientific paper
10.1103/PhysRevB.73.094518
To assess electron correlation and electron-phonon coupling in the recently discovered beta-pyrochlores KOs2O6 and RbOs2O6, we have performed specific heat measurements in magnetic fields up to 14 T. We present data from high quality single crystalline KOs2O6, showing that KOs2O6 is a strong coupling superconductor with a coupling parameter lambda_ep \approx 1.0 to 1.6 (RbOs2O6: lambda_ep \approx 1). The estimated Sommerfeld coefficient of KOs2O6, gamma=76 to 110 mJ/(mol K^2), is twice that of RbOs2O6 [gamma=44 mJ/(mol K^2)]. Using strong-coupling corrections, we extract useful thermodynamic parameters of KOs2O6. Quantifying lambda_ep allows us to determine the mass enhancement over the calculated band electronic density of states. A significant contribution in addition to the electron-phonon term of lambda_c=1.7 to 4.3 is deduced. In an effort to understand the origin of the enhancement mechanism, we also investigate an unusual energetically low-lying phonon. There are three phonon modes per RbOs2O6, suggestive of the phonon source being the rattling motion of the alkali ion. This dynamic instability of the alkali ions causes large scattering of the charge carriers which shows up in an unusual temperature dependence of the electrical resistivity.
Batlogg Bertram
Brühwiler M.
Karpinski Janusz
Kazakov Sergey M.
No associations
LandOfFree
Mass enhancement, correlations, and strong coupling superconductivity in the beta-pyrochlore KOs2O6 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Mass enhancement, correlations, and strong coupling superconductivity in the beta-pyrochlore KOs2O6, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mass enhancement, correlations, and strong coupling superconductivity in the beta-pyrochlore KOs2O6 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-223764