Anisotropic band flattening in graphene with one-dimensional superlattices

Patterning graphene with a spatially periodic potential provides a powerful means to modify its electronic properties(1-3). In particular, in twisted bilayers, coupling to the resulting moire superlattice yields an isolated flat band that hosts correlated many-body phases(4,5). However, both the symmetry and strength of the effective moire potential are constrained by the constituent crystals, limiting its tunability. Here, we have exploited the technique of dielectric patterning(6) to subject graphene to a one-dimensional electrostatic superlattice (SL)(1). We observed the emergence of multiple Dirac cones and found evidence that with increasing SL potential the main and satellite Dirac cones are sequentially flattened in the direction parallel to the SL basis vector, behaviour resulting from the interaction between the one-dimensional SL electric potential and the massless Dirac fermions hosted by graphene. Our results demonstrate the ability to induce tunable anisotropy in high-mobility two-dimensional materials, a long-desired property for novel electronic and optical applications(7,8). Moreover, these findings offer a new approach to engineering flat energy bands where electron interactions can lead to emergent properties(9).

Automated summary

By utilizing dielectric patterning to subject graphene to a one-dimensional electrostatic superlattice, multiple Dirac cones are observed, demonstrating the ability to induce tunable anisotropy in high-mobility two-dimensional materials. This offers a new approach to engineering flat energy bands where electron interactions can lead to emergent properties, which is desired for novel electronic and optical applications.