  Effect of dc electric field on transport of highly mobile 2D electrons is
studied in wide GaAs single quantum wells placed in titled magnetic fields. The
study shows that in perpendicular magnetic field resistance oscillates due to
electric field induced Landau-Zener transitions between quantum levels that
corresponds to geometric resonances between cyclotron orbits and periodic
modulation of electron density of states. Magnetic field tilt inverts these
oscillations. Surprisingly the strongest inverted oscillations are observed at
a tilt corresponding to nearly absent modulation of the electron density of
states in regime of magnetic breakdown of semiclassical electron orbits. This
phenomenon establishes an example of quantum resistance oscillations due to
Landau quantization, which occur in electron systems with a constant density of
states.
