VortexStates in Nano-Structured MgB2

We consider superconducting states of a nano-sized two-band superconductor, where one of the bands is a hole band and anotherisan electron band.We formulatethe microscopic numerical methodfortwo-band superconductorsusing the Bogoliubov-de Gennes equation and the finite element method. We show the several vortex structures under an external field.