Electronic tunneling into the vortex lattice states in superconductors in high magnetic field

STM differential conductance of a disordered extreme type-II superconductor at high magnetic fields

“…21 In a planar junction model where electrons can tunnel only along the vortex lines, i.e., along the direction of the magnetic field, the tunneling matrix elements conserve the quasiparticle quasimomenta q perpendicular to the direction of the magnetic field. 10,30 For small tunneling voltages V such that eV Յប c , the tunneling into the superconductor will take place over a very narrow span of energies around the Fermi level. 31 Therefore, it is reasonable to assume that the tunneling will preserve the Landau level index n and that all the tunneling matrix elements will be the same constant evaluated at the Fermi momenta…”