Two-band parallel conductivity at terahertz frequencies in the superconducting state of MgB${}_2$.

M. Ortolani, P. Dore, D. Di Castro +7

The optical response of the two-band superconductor MgB${}_2$ has been studied in the 0.7-4 THz range on films with very low impurity level. The effect of the high-energy $\sigma$-gap is…