Doping and charge-carrier density effects in the cuprate superconductors

David B. Tanner*, Young Duck Yoon, Axel Zibold, H. L. Liu, Manuel A. Quijada, S. W. Moore, John B. Graybeal, Beom Hoan O, John T. Markert, R. J. Kelley, Marshall Onellion, J. H. Cho

*Corresponding author for this work

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

9 Citations (Scopus)


The undoped phases of the copper-oxide materials are antiferromagnetic insulators, with a gap of 1.5 - 2 eV. Infrared spectroscopy of these compounds reveals weak absorption, possibly of magnetic origin, in this gap. When the materials are doped, oscillator strength is removed from the charge transfer band. This oscillator strength moves to low frequency, to become midinfrared and free carrier absorption. A systematic study of the electron-doped Nd 2- xCe xCuO 4-y system reveals that the growth of low-frequency oscillator strength with doping concentration x is twice as rapid as in the case of hole-doped materials, such as La 2-xSr xCuO 4. This behavior is in accord with electronic structure models based on the 3-band Hubbard model and inconsistent with one-band behavior. However, an anomaly occurs for samples which are doped to the critical concentration for superconductivity; these have a greater than expected free-carrier concentration and weaker charge-transfer bands.

Original languageEnglish
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsI. Bozovic, D. van der Marel
Number of pages11
Publication statusPublished - 1996
Externally publishedYes
EventSpectroscopic Studies of Superconductors. Part 2 (of 2) - San Jose, CA, USA, Taiwan
Duration: 1996 Jan 291996 Feb 1

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering


ConferenceSpectroscopic Studies of Superconductors. Part 2 (of 2)
CitySan Jose, CA, USA

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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