Fig. 2: Comparison of the electrical conduction in graphene devices having the ferroelectric-gated field-effect transistor configuration.
From: Charge carrier modulation in graphene on ferroelectric single-crystal substrates

a Graphene/PMNPT. b Graphene/hBN/PMNPT. The thin data lines correspond to the data taken during VG sweeps from the positive to the negative values, and the thick lines correspond to the data taken during VG sweeps from the negative to the positive values.