  This article tackles the spectral analysis of the Robin Laplacian on a smooth
bounded two-dimensional domain in the presence of a constant magnetic field. In
the semiclassical limit, a uniform description of the spectrum located between
the Landau levels is obtained. The corresponding eigenfunctions, called edge
states, are exponentially localized near the boundary. By means of a microlocal
dimensional reduction, our unifying approach allows on the one hand to derive a
very precise Weyl law and a proof of quantum magnetic oscillations for excited
states, and on the other hand to refine simultaneously old results about the
low-lying eigenvalues in the Robin case and recent ones about edge states in
the Dirichlet case.
