Ultrafast mid-infrared response of YBa(2)Cu(3)O(7-delta)
1Max-Born-Institut fur Nichtlineare Optik und Kurzzeitspektroskopie, D-12489 Berlin, Germany. Department of Physics, Clarendon Laboratory, Oxford University, Oxford OX1 3PU, UK. Department of Pure and Applied Physics, Queen's University of Belfast.
Science (New York, N.Y.)
|January 22, 2000
Summary
Researchers observed an ultrafast gap fill in high-transition-temperature superconductors. This reveals two components, one linked to superconductivity and another to pseudogap correlations, suggesting a connection to spin excitations.
Area of Science:
- Condensed matter physics
- Materials science
- Superconductivity
Background:
- High-transition-temperature superconductors exhibit a mid-infrared in-plane conductivity gap.
- The precise role of this conductivity gap in superconductivity is not fully understood.
Purpose of the Study:
- To investigate the dynamics of the mid-infrared conductivity gap in YBa(2)Cu(3)O(7-delta) after optical excitation.
- To elucidate the contributions of different electronic components to the gap recovery and their relationship with superconductivity and pseudogap phenomena.
Main Methods:
- Femtosecond time-resolved spectroscopy was employed to measure mid-infrared reflectivity.
- Nonequilibrium optical excitation was used to induce changes in the superconducting state.
Main Results:
- An ultrafast fill-in of the conductivity gap was observed.
- Two distinct recovery components were identified: a picosecond component related to the superconducting condensate and a subpicosecond component associated with pseudogap correlations in underdoped samples.
- The temperature-dependent amplitudes of these components correlate with an antiferromagnetic excitation observed via neutron scattering.
Conclusions:
- The study demonstrates the ultrafast dynamics of the conductivity gap in YBa(2)Cu(3)O(7-delta).
- Evidence suggests a coupling between charge dynamics, superconducting condensate, pseudogap correlations, and spin excitations in these materials.
