Physics – Condensed Matter – Superconductivity
Scientific paper
2009-01-08
Journal of Physics and Chemistry of Solids, VOL. 69, 2982-2985 (2008)
Physics
Condensed Matter
Superconductivity
Proceedings of SNS 2007
Scientific paper
I present results from an approach that extends the Eliashberg theory by systematic expansion in the vertex function; an essential extension at large phonon frequencies, even for weak coupling. In order to deal with computationally expensive double sums over momenta, a dynamical cluster approximation (DCA) approach is used to incorporate momentum dependence into the Eliashberg equations. First, I consider the effects of introducing partial momentum dependence on the standard Eliashberg theory using a quasi-local approximation; which I use to demonstrate that it is essential to include corrections beyond the standard theory when investigating d-wave states. Using the extended theory with vertex corrections, I compute electron and phonon spectral functions. A kink in the electronic dispersion is found in the normal state along the major symmetry directions, similar to that found in photo-emission from cuprates. The phonon spectral function shows that for weak coupling $W\lambda < \omega_0$, the dispersion for phonons has weak momentum dependence, with consequences for the theory of optical phonon mediated d-wave superconductivity, which is shown to be 2nd order in $\lambda$. In particular, examination of the order parameter vs. filling shows that vertex corrections lead to d-wave superconductivity mediated via simple optical phonons. I map out the order parameters in detail, showing that there is significant induced anisotropy in the superconducting pairing in quasi-2D systems.
No associations
LandOfFree
Kinks and d-waves from phonons: The intermediate coupling story 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 Kinks and d-waves from phonons: The intermediate coupling story, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Kinks and d-waves from phonons: The intermediate coupling story will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-62692