Emergence of moiré superlattice potential in graphene by twisted-hBN layers

Moiré superlattices formed in stacks of two or more 2D crystals with similar lattice structures have recently become excellent platforms to reveal new physics in low-dimensional systems. They are, however, highly sensitive to the angle and lattice constant differences between the associated crystals, limiting the range of the material choice and the possible moiré patterns for a given 2D crystal. Here, we present a novel approach to realize an atomically flat substrate with a periodic moiré pattern that can induce the moiré potential on the material on top by van der Waals (vdW) interactions, without suffering from the lattice and angle mismatch. By constructing a twisted hBN (thBN) moiré substrate at an angle of about 1${}^{\circ }$, we show that the graphene on top, aligned around 15${}^{\circ }$ with the neighboring hBN layers, exhibits typical transport properties under a hexagonal moiré potential, including multiple satellite Dirac points (DPs), Hofstadter butterfly effect, and Brown-Zak oscillations. All features point to the existence of the moiré potential in graphene formed by thBN with $\sim$1${}^{\circ }$ twist angle. Further statistical study shows that the twist from a parallel interface between the hBN layers is critical to induce the moiré potential. Our study demonstrates that the thBN moiré substrate can be used to investigate moiré physics in arbitrary materials without being constrained by their lattice constants.