Infrared properties of electron-doped cuprates: Tracking normal-state gaps and quantum critical behavior in Pr2 − xCexCuO4

• Published in: Europhysics letters Vol. 70; no. 2; pp. 225 - 231
• Main Authors: Zimmers, A, Tomczak, J. M, Lobo, R. P. S. M, Bontemps, N, Hill, C. P, Barr, M. C, Dagan, Y, Greene, R. L, Millis, A. J, Homes, C. C
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01-04-2005
• ISSN: 0295-5075; 1286-4854
• DOI: 10.1209/epl/i2004-10480-2

We report the temperature dependence of the infrared-visible conductivity of Pr2-xCexCuO4 thin films. When varying the doping from a non-superconducting film (x = 0.11) to a superconducting overdoped film (x = 0.17), we observe, up to optimal doping (x = 0.15), a partial gap opening. The magnitude of this gap extrapolates to zero for x ~ 0.17. A model combining a spin density wave gap and a frequency- and temperature-dependent self-energy reproduces our data reasonably well, suggesting the coexistence of magnetism and superconductivity in this material and the existence of a quantum critical point at this Ce concentration.