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Title: Determination of the optical properties of La 2-xBa xCuO₄ for several dopings, including the anomalous x=1/8 phase

The optical properties of single crystals of the high-temperature superconductor La 2-xBa xCuO₄ have been measured over a wide frequency and temperature range for light polarized in the a-b planes and along the c axis. Three different Ba concentrations have been examined, x=0.095 with a critical temperature T c=32 K, x=0.125 where the superconductivity is dramatically weakened with T c≅2.4 K, and x=0.145 with T c≅24 K. The in-plane behavior of the optical conductivity for these materials at high temperature is described by a Drude-like response with a scattering rate that decreases with temperature. Below T c in the x=0.095 and 0.145 materials there is a clear signature of the formation of a superconducting state in the optical properties allowing the superfluid density (ρ s0) and the penetration depth to be determined. In the anomalous 1/8 phase, some spectral weight shifts from lower to higher frequency (≳300 cm⁻¹) on cooling below the spin-ordering temperature T so≅42 K, associated with the onset of spin-stripe order; we discuss alternative interpretations in terms of a conventional density-wave gap versus the response to pair-density-wave superconductivity. The two dopings for which a superconducting response is observed both fall on the universal scaling line ρ s0/8≅4.4σmore » dcT c, which is consistent with the observation of strong dissipation within the a-b planes. The optical properties for light polarized along the c axis reveal an insulating character dominated by lattice vibrations, superimposed on a weak electronic background. No Josephson plasma edge is observed in the low-frequency reflectance along the c axis for x=1/8; however, sharp plasma edges are observed for x=0.095 and 0.145 below T c.« less
Authors:
; ; ; ; ; ;
Publication Date:
Type:
Publisher's Accepted Manuscript
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Volume: 85 Journal Issue: 13; Journal ID: ISSN 1098-0121
Publisher:
American Physical Society
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
OSTI Identifier:
1098706

Homes, C. C., Hücker, M., Li, Q., Xu, Z. J., Wen, J. S., Gu, G. D., and Tranquada, J. M.. Determination of the optical properties of La2-xBaxCuO₄ for several dopings, including the anomalous x=1/8 phase. United States: N. p., Web. doi:10.1103/PhysRevB.85.134510.
Homes, C. C., Hücker, M., Li, Q., Xu, Z. J., Wen, J. S., Gu, G. D., & Tranquada, J. M.. Determination of the optical properties of La2-xBaxCuO₄ for several dopings, including the anomalous x=1/8 phase. United States. doi:10.1103/PhysRevB.85.134510.
Homes, C. C., Hücker, M., Li, Q., Xu, Z. J., Wen, J. S., Gu, G. D., and Tranquada, J. M.. 2012. "Determination of the optical properties of La2-xBaxCuO₄ for several dopings, including the anomalous x=1/8 phase". United States. doi:10.1103/PhysRevB.85.134510.
@article{osti_1098706,
title = {Determination of the optical properties of La2-xBaxCuO₄ for several dopings, including the anomalous x=1/8 phase},
author = {Homes, C. C. and Hücker, M. and Li, Q. and Xu, Z. J. and Wen, J. S. and Gu, G. D. and Tranquada, J. M.},
abstractNote = {The optical properties of single crystals of the high-temperature superconductor La2-xBaxCuO₄ have been measured over a wide frequency and temperature range for light polarized in the a-b planes and along the c axis. Three different Ba concentrations have been examined, x=0.095 with a critical temperature Tc=32 K, x=0.125 where the superconductivity is dramatically weakened with Tc≅2.4 K, and x=0.145 with Tc≅24 K. The in-plane behavior of the optical conductivity for these materials at high temperature is described by a Drude-like response with a scattering rate that decreases with temperature. Below Tc in the x=0.095 and 0.145 materials there is a clear signature of the formation of a superconducting state in the optical properties allowing the superfluid density (ρs0) and the penetration depth to be determined. In the anomalous 1/8 phase, some spectral weight shifts from lower to higher frequency (≳300 cm⁻¹) on cooling below the spin-ordering temperature Tso≅42 K, associated with the onset of spin-stripe order; we discuss alternative interpretations in terms of a conventional density-wave gap versus the response to pair-density-wave superconductivity. The two dopings for which a superconducting response is observed both fall on the universal scaling line ρs0/8≅4.4σdcTc, which is consistent with the observation of strong dissipation within the a-b planes. The optical properties for light polarized along the c axis reveal an insulating character dominated by lattice vibrations, superimposed on a weak electronic background. No Josephson plasma edge is observed in the low-frequency reflectance along the c axis for x=1/8; however, sharp plasma edges are observed for x=0.095 and 0.145 below Tc.},
doi = {10.1103/PhysRevB.85.134510},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 13,
volume = 85,
place = {United States},
year = {2012},
month = {4}
}

Works referenced in this record:

Ordering, metastability and phase transitions in two-dimensional systems
journal, April 1973
  • Kosterlitz, J M; Thouless, D J
  • Journal of Physics C: Solid State Physics, Vol. 6, Issue 7, p. 1181-1203
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