Magnetotransport in a laterally confined two-dimensional electron gas (2DEG) can exhibit modified scattering channels owing to a tilted Hall potential. Transitions of electrons between Landau levels with shifted guiding centers can be accomplished through a Zener tunneling mechanism, and make a significant contribution to the magnetoresistance. A remarkable oscillation effect in weak field magnetoresistance has been observed in high-mobility 2DEGs in $\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}\text{−}\mathrm{A}\mathrm{l}{\mathrm{G}}_{\mathrm{a}}{\mathrm{A}}_{\mathrm{s}}$ heterostructures, and can be well explained by the Zener mechanism.

• Received 9 April 2002

DOI:https://doi.org/10.1103/PhysRevLett.89.076801