  We study electronic transport in graphene under the influence of a
transversal magnetic field $\f{B}(\f{r})=B(x)\f{e}_z$ with the asymptotics
$B(x\to\pm\infty)=\pm B_0$, which could be realized via a folded graphene sheet
in a constant magnetic field, for example. By solving the effective Dirac
equation, we find robust modes with a finite energy gap which propagate along
the fold -- where particles and holes move in opposite directions. Exciting
these particle-hole pairs with incident photons would then generate a nearly
perfect charge separation and thus a strong magneto-thermoelectric
(Nernst-Ettingshausen) or magneto-photoelectric effect -- even at room
temperature.
