  The Goos-Hanchen (GH) effect is an interference effect on total internal
reflection at an interface, resulting in a shift sigma of the reflected beam
along the interface. We show that the GH effect at a p-n interface in graphene
depends on the pseudospin (sublattice) degree of freedom of the massless Dirac
fermions, and find a sign change of sigma at angle of incidence
alpha*=arcsin[sin alpha_c]^1/2 determined by the critical angle alpha_c for
total reflection. In an n-doped channel with p-doped boundaries the GH effect
doubles the degeneracy of the lowest propagating mode, introducing a two-fold
degeneracy on top of the usual spin and valley degeneracies. This can be
observed as a stepwise increase by 8e^2/h of the conductance with increasing
channel width.
