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Title: Ultrafast optical pump terahertz-probe spectroscopy of strongly correlated electron materials.

Abstract

We have used optical-pump far-infrared probe spectroscopy to probe the low energy electron dynamics of high temperature superconductors and colossal magnetoresistance manganites. For the superconductor YBa2Cu3O7, picosecond conductivity measurements probe the interplay between Cooper-pairs and quasiparticles. In optimally doped films, the recovery time for long-range phase-coherent pairing increases from {approx}1.5 ps at 4K to {approx}3.5 ps near Tc, consistent with the closing of the superconducting gap. For underdoped films, the measured recovery time is temperature independent (3.5 ps) in accordance with the presence of a pseudogap. Ultrafast picosecond measurements of optically induced changes in the absolute conductivity of La0:7M0:3MnO3 thin films (M = Ca, Sr) from 10K to {approx}0.9Tc reveal a two-component relaxation. A fast, {approx}2 ps, conductivity decrease arises from optically induced modification of the effective phonon temperature. The slower component, related to spin-lattice relaxation, has a lifetime that increases upon approaching Tc from below in accordance with an increasing spin specific heat. Our results indicate that for T<<Tc, the conductivity is determined by incoherent phonons while spin fluctuations dominate near Tc.

Authors:
 [1]; ;  [2]; ; ;  [3]
  1. (Richard D.)
  2. (Verner K.)
  3. (Stuart A.)
Publication Date:
Research Org.:
Los Alamos National Laboratory
Sponsoring Org.:
USDOE
OSTI Identifier:
975709
Report Number(s):
LA-UR-01-4821
TRN: US1006764
Resource Type:
Conference
Resource Relation:
Conference: "Submitted to: Invited paper for Proceedings of the 26th International Conference on Infrared and Millimeter Waves"
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COOPER PAIRS; ELECTRONS; LIFETIME; MAGNETORESISTANCE; MODIFICATIONS; PHONONS; PROBES; RELAXATION; SPECTROSCOPY; SPIN; SPIN-LATTICE RELAXATION; SUPERCONDUCTORS; THIN FILMS; MATERIALS

Citation Formats

Averitt, R. D., Taylor, Antoinette J.,, Thorsmølle, V. K., Jia, Quanxi, Lobad, A. I., and Trugman, S. A. Ultrafast optical pump terahertz-probe spectroscopy of strongly correlated electron materials.. United States: N. p., 2001. Web.
Averitt, R. D., Taylor, Antoinette J.,, Thorsmølle, V. K., Jia, Quanxi, Lobad, A. I., & Trugman, S. A. Ultrafast optical pump terahertz-probe spectroscopy of strongly correlated electron materials.. United States.
Averitt, R. D., Taylor, Antoinette J.,, Thorsmølle, V. K., Jia, Quanxi, Lobad, A. I., and Trugman, S. A. Mon . "Ultrafast optical pump terahertz-probe spectroscopy of strongly correlated electron materials.". United States. https://www.osti.gov/servlets/purl/975709.
@article{osti_975709,
title = {Ultrafast optical pump terahertz-probe spectroscopy of strongly correlated electron materials.},
author = {Averitt, R. D. and Taylor, Antoinette J., and Thorsmølle, V. K. and Jia, Quanxi and Lobad, A. I. and Trugman, S. A.},
abstractNote = {We have used optical-pump far-infrared probe spectroscopy to probe the low energy electron dynamics of high temperature superconductors and colossal magnetoresistance manganites. For the superconductor YBa2Cu3O7, picosecond conductivity measurements probe the interplay between Cooper-pairs and quasiparticles. In optimally doped films, the recovery time for long-range phase-coherent pairing increases from {approx}1.5 ps at 4K to {approx}3.5 ps near Tc, consistent with the closing of the superconducting gap. For underdoped films, the measured recovery time is temperature independent (3.5 ps) in accordance with the presence of a pseudogap. Ultrafast picosecond measurements of optically induced changes in the absolute conductivity of La0:7M0:3MnO3 thin films (M = Ca, Sr) from 10K to {approx}0.9Tc reveal a two-component relaxation. A fast, {approx}2 ps, conductivity decrease arises from optically induced modification of the effective phonon temperature. The slower component, related to spin-lattice relaxation, has a lifetime that increases upon approaching Tc from below in accordance with an increasing spin specific heat. Our results indicate that for T<<Tc, the conductivity is determined by incoherent phonons while spin fluctuations dominate near Tc.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2001},
month = {1}
}

Conference:
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