Infrared studies of high Tc superconductors

D. B. Tanner, G. L. Carr, Feng Gao, S. L. Herr, K. Kamarás, J. S. Kim, C. D. Porter, D. B. Romero, G. R. Stewart, N. Tache, S. Etemad, T. Venkatesan, B. Dutta, A. Inam, X. D. Wu, M. Reedyk, D. A. Bonn, J. D. Garrett, J. E. Greedan, T. Timusk

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The authors discuss the IR reflectance of epitaxially grown laser-deposited films of YBa2Cu3O7-δ and of single crystals of Bi2Sr2CaCu2O8. Below Tc, both show zero absorption at low frequencies (120-140 cm for YBa2Cu3O7-δ and 250-300/cm for bisco). At higher frequencies (420-470/cm for YBa2Cu3O7-δ and 470-520/cm for bisco), there is a characteristic knee in the reflectance and a corresponding minimum in σ1(ω). Although these features are revealed clearly below Tc, it is concluded that neither should be assigned to the superconducting gap. Both are present in the normal state. Furthermore, the clean limit holds, making the gap difficult to see by IR absorption. There are two other reasons why the authors believe that neither of the obvious IR features is the superconducting gap. First, they occur at nearly the same energy in reduced Tc crystals and Tc ≈ 91 K films and thus do not scale with Tc. Second, they occur at different frequencies in YBa2Cu3O7 and Bi2Sr2CaCu2O8, although Tc is nearly identical for these materials. Alternate interpretations are that the mid-IR band is a direct electronic absorption, whose energy is determined by the material, and that the minimum is a phonon feature.

Original languageEnglish
Title of host publicationXVII International Conference on Quantum Electronics. Digest of
PublisherPubl by IEEE
Pages110
Number of pages1
Publication statusPublished - 1990
Event17th International Conference on Quantum Electronics - IQEC '90 - Anaheim, CA, USA
Duration: May 21 1990May 25 1990

Other

Other17th International Conference on Quantum Electronics - IQEC '90
CityAnaheim, CA, USA
Period5/21/905/25/90

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Superconducting materials
Infrared radiation
Single crystals
Crystals
Lasers

ASJC Scopus subject areas

  • Engineering(all)

Cite this

Tanner, D. B., Carr, G. L., Gao, F., Herr, S. L., Kamarás, K., Kim, J. S., ... Timusk, T. (1990). Infrared studies of high Tc superconductors. In XVII International Conference on Quantum Electronics. Digest of (pp. 110). Publ by IEEE.

Infrared studies of high Tc superconductors. / Tanner, D. B.; Carr, G. L.; Gao, Feng; Herr, S. L.; Kamarás, K.; Kim, J. S.; Porter, C. D.; Romero, D. B.; Stewart, G. R.; Tache, N.; Etemad, S.; Venkatesan, T.; Dutta, B.; Inam, A.; Wu, X. D.; Reedyk, M.; Bonn, D. A.; Garrett, J. D.; Greedan, J. E.; Timusk, T.

XVII International Conference on Quantum Electronics. Digest of. Publ by IEEE, 1990. p. 110.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Tanner, DB, Carr, GL, Gao, F, Herr, SL, Kamarás, K, Kim, JS, Porter, CD, Romero, DB, Stewart, GR, Tache, N, Etemad, S, Venkatesan, T, Dutta, B, Inam, A, Wu, XD, Reedyk, M, Bonn, DA, Garrett, JD, Greedan, JE & Timusk, T 1990, Infrared studies of high Tc superconductors. in XVII International Conference on Quantum Electronics. Digest of. Publ by IEEE, pp. 110, 17th International Conference on Quantum Electronics - IQEC '90, Anaheim, CA, USA, 5/21/90.
Tanner DB, Carr GL, Gao F, Herr SL, Kamarás K, Kim JS et al. Infrared studies of high Tc superconductors. In XVII International Conference on Quantum Electronics. Digest of. Publ by IEEE. 1990. p. 110
Tanner, D. B. ; Carr, G. L. ; Gao, Feng ; Herr, S. L. ; Kamarás, K. ; Kim, J. S. ; Porter, C. D. ; Romero, D. B. ; Stewart, G. R. ; Tache, N. ; Etemad, S. ; Venkatesan, T. ; Dutta, B. ; Inam, A. ; Wu, X. D. ; Reedyk, M. ; Bonn, D. A. ; Garrett, J. D. ; Greedan, J. E. ; Timusk, T. / Infrared studies of high Tc superconductors. XVII International Conference on Quantum Electronics. Digest of. Publ by IEEE, 1990. pp. 110
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AU - Herr, S. L.

AU - Kamarás, K.

AU - Kim, J. S.

AU - Porter, C. D.

AU - Romero, D. B.

AU - Stewart, G. R.

AU - Tache, N.

AU - Etemad, S.

AU - Venkatesan, T.

AU - Dutta, B.

AU - Inam, A.

AU - Wu, X. D.

AU - Reedyk, M.

AU - Bonn, D. A.

AU - Garrett, J. D.

AU - Greedan, J. E.

AU - Timusk, T.

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N2 - The authors discuss the IR reflectance of epitaxially grown laser-deposited films of YBa2Cu3O7-δ and of single crystals of Bi2Sr2CaCu2O8. Below Tc, both show zero absorption at low frequencies (120-140 cm for YBa2Cu3O7-δ and 250-300/cm for bisco). At higher frequencies (420-470/cm for YBa2Cu3O7-δ and 470-520/cm for bisco), there is a characteristic knee in the reflectance and a corresponding minimum in σ1(ω). Although these features are revealed clearly below Tc, it is concluded that neither should be assigned to the superconducting gap. Both are present in the normal state. Furthermore, the clean limit holds, making the gap difficult to see by IR absorption. There are two other reasons why the authors believe that neither of the obvious IR features is the superconducting gap. First, they occur at nearly the same energy in reduced Tc crystals and Tc ≈ 91 K films and thus do not scale with Tc. Second, they occur at different frequencies in YBa2Cu3O7 and Bi2Sr2CaCu2O8, although Tc is nearly identical for these materials. Alternate interpretations are that the mid-IR band is a direct electronic absorption, whose energy is determined by the material, and that the minimum is a phonon feature.

AB - The authors discuss the IR reflectance of epitaxially grown laser-deposited films of YBa2Cu3O7-δ and of single crystals of Bi2Sr2CaCu2O8. Below Tc, both show zero absorption at low frequencies (120-140 cm for YBa2Cu3O7-δ and 250-300/cm for bisco). At higher frequencies (420-470/cm for YBa2Cu3O7-δ and 470-520/cm for bisco), there is a characteristic knee in the reflectance and a corresponding minimum in σ1(ω). Although these features are revealed clearly below Tc, it is concluded that neither should be assigned to the superconducting gap. Both are present in the normal state. Furthermore, the clean limit holds, making the gap difficult to see by IR absorption. There are two other reasons why the authors believe that neither of the obvious IR features is the superconducting gap. First, they occur at nearly the same energy in reduced Tc crystals and Tc ≈ 91 K films and thus do not scale with Tc. Second, they occur at different frequencies in YBa2Cu3O7 and Bi2Sr2CaCu2O8, although Tc is nearly identical for these materials. Alternate interpretations are that the mid-IR band is a direct electronic absorption, whose energy is determined by the material, and that the minimum is a phonon feature.

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