Charge transport in normal metal–magnesiumdiboride junctions

The influence of the multiband nature of superconductivity in MgB2 on the charge transport properties of MgB2 tunnel junctions and normal metal–MgB2 heterostructures has been theoretically modeled and experimentally explored. The conductance as function of barrier height and angle is calculated. Planar c-axis tunnel junctions are realized in which two gaps are resolved in the tunnel spectrum. For junctions with additional conductance in the direction of the crystallographic a–b plane we observe a sharp resonance that can possibly be attributed to a Leggett mode