Fig. 1: Electric hysteresis of the OSH device 1.
From: Room temperature ferroelectricity in monolayer graphene sandwiched between hexagonal boron nitride
a Atomic structure of the OSHs at two metastable states. b Structural evolution of the OSHs under co-sliding motions of graphene and hBN. White, gray and green spheres denote N, C and B atoms, respectively. Pink background marks the stationary bottom hBN layer while graphene and top hBN layers co-slide during ferroelectric switch. Brown and green arrows mark the sliding direction of graphene and hBN, respectively. c An optical image of one OSH stack. Scale bar: 10 μm. The zigzag edges of top and bottom hBN flakes are marked by red and yellow dashed lines, respectively. d Band structure of graphene/hBN heterolayer with zero twist angle. In the OSH device 1, the graphene electronic band is folded by graphene/hBN moiré superlattice potential, which clones the Dirac point (DP) at the superlattice band edges, termed as secondary Dirac points DP1 and DP2, respectively (below and above the main DP, Fig. 1d)23. e Top: four-probe longitudinal resistance Rxx of OSH device 1 during forward (blue) and backward (red) sweeps of back-gate voltages, at T = 1.5 K. Bottom: Hall resistance Rxy hysteresis at B = 0.05 T.
