Anisotropic band flattening in graphene with 1D superlattices

TL;DR

This paper demonstrates how dielectric patterning creates a tunable one-dimensional superlattice in graphene, leading to anisotropic band flattening and the potential for novel electronic and optical applications.

Contribution

It introduces a new dielectric patterning technique to induce tunable anisotropic band flattening in graphene with 1D superlattices, expanding control over its electronic properties.

Findings

Sequential flattening of Dirac cones with increasing superlattice potential

Observation of multiple Dirac cones and induced anisotropic transport

Demonstration of a new method to engineer flat energy bands in 2D materials

Abstract

Patterning graphene with a spatially-periodic potential provides a powerful means to modify its electronic properties. Dramatic effects have been demonstrated in twisted bilayers where coupling to the resulting moir\'e-superlattice yields an isolated flat band that hosts correlated many-body phases. However, both the symmetry and strength of the effective moir\'e potential are constrained by the constituent crystals, limiting its tunability. Here we exploit the technique of dielectric patterning to subject graphene to a one-dimensional electrostatic superlattice (SL). We observe the emergence of multiple Dirac cones and find evidence that with increasing SL potential the main and satellite Dirac cones are sequentially flattened in the direction parallel to the SL basis vector. Our results demonstrate the ability to induce tunable transport anisotropy in high mobility two-dimensional materials, a long-desired property for novel electronic and optical applications, as well as a new approach to engineering flat energy bands where electron-electron interactions can lead to emergent properties.