@inproceedings{e887494e690d4a399f3a41c6a9b3e9e3,
title = "Doping and charge-carrier density effects in the cuprate superconductors",
abstract = "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.",
author = "Tanner, {David B.} and Yoon, {Young Duck} and Axel Zibold and Liu, {H. L.} and Quijada, {Manuel A.} and Moore, {S. W.} and Graybeal, {John B.} and O, {Beom Hoan} and Markert, {John T.} and Kelley, {R. J.} and Marshall Onellion and Cho, {J. H.}",
year = "1996",
language = "English",
isbn = "0819420700",
series = "Proceedings of SPIE - The International Society for Optical Engineering",
number = "1/-",
pages = "13--23",
editor = "I. Bozovic and {van der Marel}, D.",
booktitle = "Proceedings of SPIE - The International Society for Optical Engineering",
edition = "1/-",
note = "Spectroscopic Studies of Superconductors. Part 2 (of 2) ; Conference date: 29-01-1996 Through 01-02-1996",
}