Figure 1

EG device description. (a) The optical image of the device shows the graphene Hall bar outlined by a red dashed line and the encapsulating h-BN layer enclosed by a blue dotted line. The width of the Hall bar channel is marked with a white arrow. Each used device contact is given a numerical designation and the top gates are labelled as G1, G2 and G3 and represented as digitally artificial colors of yellow, orange, and bronze, respectively. The upper (UE) and lower edges (LE) are marked with dashed white lines. The direction of the positive magnetic field for the measurements is out of the page. (b) The atomic force microscope image of the pnJ shows the magnified region enclosed by the black square in (a). (c) An illustration device’s cross section is provided.