Extended Data Fig. 6: Probing the out-of-plane electrical polarization using the top MLG sensor in device H4.
From: Unconventional ferroelectricity in moiré heterostructures
a, Experimental configuration for measurements of the conductance of the BLG. b, Measured conductance of the BLG as a function of VBG (top gate is grounded). The red and blue curves correspond to the forward and backward VBG scans, respectively. The vertical dashed lines denote the VBG values that correspond to the charge-neutrality point of the BLG for forward and backward scans. c, Experimental configuration for the measurements of the conductance of the tp-MLG with gate voltage VBG applied to bottom metal gate and the BLG grounded. d, Measured conductance of the tp-MLG as a function of VBG with the experimental configuration in c. The gate voltages are the same as in b (Methods). The red and blue dots denote the conductance of the tp-MLG when the BLG is charge neutral. e, Experimental configuration for the measurements of the conductance of the tp-MLG with gate voltage VBL applied to the BLG. f, Measurements of the conductance of the tp-MLG as a function of VBL with the experimental configuration in e. The conductance of the monolayer at the red and blue dots in d can be inversely mapped to two different VBL values, which corresponds to the difference of electrostatic potentials on the top surface of BLG induced by ferroelectric switching (Methods). The in-plane bias voltage VSD was kept below 1 mV for all the measurements.
