Magnetoresistance oscillation in a two-dimensional electron gas under periodic modulation of electric and magnetic fields

We have studied oscillatory magnetoresistance (Weiss oscillation) in a two-dimensional electron gas (2DEG) subjected to a one-dimensional periodic modulation of both electric and magnetic fields. The relative amplitude of the two types of modulation can be controlled by applying a bias voltage to a gate consisting of a periodic array of ferromagnetic metal stripes. Allowing the magnetic modulation to dominate by applying +500 mV to the gate, we succeeded in observing magnetic Weiss oscillation which is characterized by peak/valley inversion in the magnetoresistance oscillation and not with regard to its well-known electric counterpart. The oscillation curve shows continuous phase shift with smaller gate biases, until it reaches the peak/valley location of electric Weiss oscillation at about -250 mV.