An investigation was made of the vortex state in a 2-band superconductor with strong intraband and weak interband electronic scattering rates. Coupled Usadel equations were solved numerically, and the distributions of the pair potentials and local densities of states were calculated for 2 bands at different values of magnetic fields. The existence of 2 distinct length scales corresponding to different bands was demonstrated. The results provided qualitative interpretation of recent scanning tunneling microscopy experiments on vortex structure imaging in MgB2.

Mixed State of a Dirty Two-Band Superconductor - Application to MgB2. A.E.Koshelev, A.A.Golubov: Physical Review Letters, 2003, 90[17], 177002 (3pp)