Infrared behavior of superconducting diamond. (a) R(ω) in the THz range at 10 K. In the inset R(ω) is shown at 300 K up to 20000 cm−1. (b) The real part of the optical conductivity showing a gap opening and a full recovery for , as expected for a BCS superconductor in the dirty limit. (c) The inverse square of the penetration depth, obtained from missing area in (b) (experimental points), is compared with the BCS dirty superconductor behavior, once normalized to zero temperature (grey line).
