Article abstract
Nature Physics 2, 537 - 543 (2006)
doi:10.1038/nphys362
Subject Categories: Condensed-matter physics | Materials physics
Two energy scales and two distinct quasiparticle dynamics in the superconducting state of underdoped cuprates
M. Le Tacon1,2, A. Sacuto1,2, A. Georges3, G. Kotliar3,4,5, Y. Gallais6, D. Colson7 and A. Forget7
Abstract
The superconducting temperature Tc of hole-doped high-temperature superconductors has a dome-like shape as a function of hole concentration, with a maximum Tc at 'optimal' doping. On the underdoped side, the superconducting state is often described in terms of one energy scale, associated with the maximum of the d-wave gap (at the antinodes), which increases as the doping decreases. Here, we report electronic Raman scattering experiments that show a second energy scale in the gap function: the slope of the gap at the nodes, which decreases with decreasing doping. Our measurements also reveal two distinct quasiparticle dynamics; electronic coherence persists down to low doping levels at the nodes, whereas antinodal quasiparticles become incoherent. Using a sum-rule, we find that the low-frequency Raman response and the temperature dependence of the superfluid density, both controlled by nodal excitations, behave in a qualitatively similar manner with doping variation.
- Laboratoire Matériaux et Phénomènes Quantiques (UMR 7162 CNRS), Université Paris 7, 2 place Jussieu 75251 Paris, France
- Laboratoire de Physique du Solide, ESPCI, 10 rue Vauquelin 75231 Paris, France
- Centre de Physique Théorique, Ecole Polytechnique, 91128 Palaiseau Cedex, France
- Service de Physique Théorique, CEA-Saclay, 91191 Gif-sur-Yvette, France
- Serin Physics Laboratory, Rutgers University, USA
- Departments of Physics and Applied Physics, Columbia University New York, New York 10027, USA
- Service de Physique de l'Etat Condensé (CNRS URA 2464), DSM/DRECAM/SPEC, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
Correspondence to: M. Le Tacon1,2 e-mail: mathieu.le-tacon@espci.fr
MORE ARTICLES LIKE THIS
These links to content published by NPG are automatically generated.
NEWS AND VIEWS
High-temperature superconductivity Fits and startsNature Physics News and Views (01 Apr 2008)
Superconductors Opening the gapNature News and Views (12 Mar 1998)
See all 6 matches for News And ViewsRESEARCH
How Cooper pairs vanish approaching the Mott insulator in Bi 2 Sr 2 CaCu 2 O 8+&dgr;Nature Article (28 Aug 2008)
Evolution of the electronic excitation spectrum with strongly diminishing hole density in superconducting Bi 2 Sr 2 CaCu 2 O 8+δNature Physics Article (01 Apr 2008)
See all 76 matches for Research
