Volume 82, Number 2, April 2008
Article Number 27002
Number of page(s) 5
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
Published online 26 March 2008
EPL, 82 (2008) 27002
DOI: 10.1209/0295-5075/82/27002

Fermi surface arcs and the infrared conductivity of underdoped YBa2Cu3O6.50

J. Hwang1, J. P. Carbotte1, 2 and T. Timusk1, 2

1  Department of Physics and Astronomy, McMaster University - Hamilton, Ontario L8S 4M1, Canada
2  The Canadian Institute for Advanced Research - Toronto, Ontario M5G 1Z8, Canada

received 22 January 2008; accepted in final form 21 February 2008; published April 2008
published online 26 March 2008

We reanalyze the data on the in-plane far infrared conductivity of underdoped orthoII YBa2Cu3O6.50 (YBCO6.50) in terms of a model in which a pseudogap opens on part of the Fermi surface with the remaining ungapped piece proportional to the temperature. The motivation for our model comes from recent angle-resolved photoemission spectroscopy data in underdoped Bi2Sr2CaCu2O$_{8+\delta}$ (Bi-2212), which have revealed the existence of arcs on the Fermi surface. We find the optical data to be consistent with arc formation. In addition we find some evidence that the electronic states lost below the pseudogap energy $\Delta _{pg}$ are recovered in the energy region immediately above it at least for temperatures near Tc.

74.72.-h - Cuprate superconductors (high-Tc and insulating parent compounds).
74.25.Gz - Optical properties.
74.72.Bk - Y-based cuprates.

© EPLA 2008