### Session X25: Superconductivity: Optical, Raman and Other Spectroscopies

2:30 PM–5:18 PM, Thursday, March 24, 2011
Room: D166

Chair: David Tanner, University of Florida

Abstract ID: BAPS.2011.MAR.X25.1

### Abstract: X25.00001 : How can we relate the critical temperature and the superconducting gap amplitude in cuprate superconductors?

2:30 PM–2:42 PM

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#### Authors:

Alain Sacuto
(Laboratoire Mat\'eriaux et Ph\'enom\enes Quantiques, CNRS Universit\'e Paris Diderot - Paris 7, Paris Cedex 13, France)

Seabstien Blanc
(Laboratoire Mat\'eriaux et Ph\'enom\enes Quantiques, CNRS Universit\'e Paris Diderot - Paris 7, Paris Cedex 13, France)

Yann Gallais
(Laboratoire Mat\'eriaux et Ph\'enom\enes Quantiques, CNRS Universit\'e Paris Diderot - Paris 7, Paris Cedex 13, France)

Maximilien Cazayous
(Laboratoire Mat\'eriaux et Ph\'enom\enes Quantiques, CNRS Universit\'e Paris Diderot - Paris 7, Paris Cedex 13, France)

Marie Aude Measson
(Laboratoire Mat\'eriaux et Ph\'enom\`enes Quantiques, CNRS Universit\'e Paris Diderot - Paris 7, Paris Cedex 13, France)

J.S. Wen
(Matter Physics and Materials Science, Brookhaven National Laboratory (BNL), USA)

Z.J. Xu
(Matter Physics and Materials Science, Brookhaven National Laboratory (BNL), USA)

Genda Gu
(Matter Physics and Materials Science, Brookhaven National Laboratory (BNL), USA)

We explore the superconducting state of hole-doped cuprates by electronic Raman scattering as a function of both temperature and doping level. We observe a loss of coherent quasi-particles in the anti-nodal region and show that coherent Bogoliubov quasiparticles are confined around the nodes. This contrasts to conventional superconductors where superconductivity develops uniformly along the normal-state Fermi surface. We define the fraction of coherent Fermi surface, f$_{c}$ around the nodes for which quasi-particles are well defined and superconductivity sets in. We establish that T$_{c} \quad \propto$ f$_{c}\Delta _{max}$. $\Delta _{max}$ is the maximum amplitude of the d-wave superconducting gap. This new relation differs from the standard BCS theory and gives us some clues for increasing T$_{c}$ in the cuprates. S. Blanc et al. Phys. Rev. B \textbf{82}, 144516 (2010); S. Blanc et al. Phys. Rev. B \textbf{80}, 140502 (2009).

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2011.MAR.X25.1