The onset of superconductivity in semi-infinite strips

The existence of a superconducting branch bifurcating from the normal state is proved in semi-infinite strips. It is proved that the critical magnetic field at which bifurcation takes place, or the onset field, for a semi-inf inite strip is greater than the onset field for an infinite strip with the same width. In addition we find the loci of the vortices far away from the corners and show convergence of the bifurcating modes in long rectangles to those in the semi-infinite strip with the same width. (C) 2000 American In stitute of Physics. [S0022-2488(00)01112-9].