Multi-gap superconductivity in a BaFe1.84Co0.16As2 film from optical measurements at terahertz frequencies
A. Perucchi, L. Baldassarre, S. Lupi, J. Y. Jiang, J. D. Weiss, E. E. Hellstrom, S. Lee, C. W. Bark, C. B. Eom, M. Putti, I. Pallecchi, C. Marini and P. Dore