Strong coupling superconductivity mediated by three-dimensional anharmonic phonons

Details Strong coupling superconductivity mediated by three-dimensional anharmonic phonons Strong coupling superconductivity mediated by three-dimensional anharmonic phonons

2010-03-13

arxiv.org/abs/1003.2709v2

Physics

Condensed Matter

Superconductivity

16 pages, 17 figures, Phys. Rev. B 81, 134503 (2010).

Scientific paper

We investigate three dimensional anharmonic phonons in tetrahedral symmetry and superconductivity mediated by these phonons. Three dimensional anharmonic phonon spectra are calculated directly by solving Schr\"odinger equation and the superconducting transition temperature is determined by using the theory of strong coupling superconductivity assuming an isotropic gap function. With increasing the third order anharmonicity $b$ of the tetrahedral ion potential, we find a crossover in the energy spectrum to a quantum tunneling regime. We obtain strongly enhanced transition temperatures around the crossover point. We also investigate the anharmonic effects on the Debye-Waller factor, the phonon spectral functions and the density profile, as a function of the anharmonicity $b$ and temperature. The isomorphic first order transition observed in KOs_2O_6 is discussed in terms of the first excited state energy $\Delta$, and the coupling constant $\lambda$ in the strong coupling theory of superconductivity. Our results suggest the decrease of $\lambda$ and increase of $\Delta$ below the first order transition temperature. We point out that the change in the oscillation amplitude and characterizes this isomorphic transition. The chemical trends of the superconducting transition temperature, $\lambda$, and $\Delta$ in the $\beta$-pyrochlore compounds are also discussed.

Affiliated with

Also associated with

No associations

Rating

Strong coupling superconductivity mediated by three-dimensional anharmonic phonons 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 Strong coupling superconductivity mediated by three-dimensional anharmonic phonons, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Strong coupling superconductivity mediated by three-dimensional anharmonic phonons will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-192139