Magnetotransport properties of hall-bar with focused-ion-beam written in-plane-gate

Abstract In an AlGaAs/GaAs heterostructure magnetotransport has been measured along an edge which can be influenced by an in-plane-gate. The in-plane-gate has been produced by writing an isolating line with a focused-ion beam of 100 keV Ga + -ions. A drastic increase of the amplitude of the Shubnikov-de Haas oscillations is observed for positive gate voltages applied to the in-plane-gate. This increase in amplitude is attributed to an increased coupling between edge states due to a decreased distance to the scattering centers generated by the focused-ion beam.