Optical properties of BaFe2-xCoxAs2

E. van Heumen, Y. Huang, S. de Jong, A. B. Kuzmenko, M. S. Golden, D. van der Marel
2010 Europhysics letters  
We present detailed temperature dependent optical data on BaFe_2-xCo_xAs_2 (BCFA), with x = 0.14, between 4 meV and 6.5 eV. We analyze our spectra to determine the main optical parameters and show that in this material the interband conductivity already starts around 10 meV. We determine the superfluid density to be 2.2 10^7 cm^-2, which places optimally doped BFCA close to the Uemura line. Our experimental data shows clear signs of a superconducting gap with 2Δ_1 = 6.2 ± 0.8 meV. In addition
more » ... show that the optical spectra are consistent with the presence of an additional band of strongly scattered carriers with a larger gap, 2Δ_2 = 14 ± 2 meV.
doi:10.1209/0295-5075/90/37005 fatcat:estkdsduuja7xpgcntwjkpgtyy