  The possibility of multi-band conductivity and multi-gap superconductivity is
explored in oriented V3Si thin films by means of reflectance and transmittance
measurements at terahertz frequencies. The temperature dependence of the
transmittance spectra in the normal state gives evidence of two bands
contributing to the film conductivity. This outcome is consistent with
electronic structure calculations performed within density functional theory.
On this basis, we performed a detailed data analysis and found that all optical
data can be consistently accounted for within a two-band framework, with the
presence of two optical gaps in the superconducting state corresponding to
2D=kTc values close to 1.8 and 3.8.
