The investigation of the temperature dependences of microwave surface
impedance and complex conductivity of V3Si single crystals with different
stoichiometry allowed to observe a number of peculiarities which are in
remarkable contradiction with single-gap Bardeen-Cooper-Schrieffer theory. At
the same time, they can be well described by two-band model of
superconductivity, thus strongly evidencing the existence of two distinct
energy gaps with zero-temperature values Delta1~1.8Tc and Delta2~0.95Tc in
V3Si.Comment: Submitted to Europhysics Letter