Dirac Fermion Cloning, Moir$\acute{\mathbf{e}}$ Flat Bands and Magic Lattice Constants in Epitaxial Monolayer Graphene

Abstract

Tuning interactions between Dirac states in graphene has attracted enormous interest because it can modify the electronic spectrum of the two-dimensional material, enhance electron correlations, and give rise to novel condensed-matter phases such as superconductors, Mott insulators, Wigner crystals and quantum anomalous Hall insulators. Previous works predominantly focus on the flat band dispersion of coupled Dirac states from different graphene layers. In this work, we propose a new route to realizing flat band physics in monolayer graphene under a periodic modulation from substrates. We take gaphene/SiC heterostructure as a role model and demonstrate experimentally the substrate modulation leads to Dirac fermion cloning and consequently, the proximity of the two Dirac cones of monolayer graphene in momentum space. Our theoretical modeling captures the cloning mechanism of Dirac states and indicates that flat bands can emerge at certain magic lattice constants of substrate when the period of modulation becomes nearly commensurate with the $(\sqrt{3}\times \sqrt{3})R30^{\circ }$ supercell of graphene. The results show that the epitaxial monolayer graphene is a promising platform for exploring exotic many-body quantum phases arising from interactions between Dirac electrons.

References in corpus (12)

• The electronic properties of graphene
• Boron nitride substrates for high-quality graphene electronics
• Chiral tunneling and the Klein paradox in graphene
• Vertical Field Effect Transistor based on Graphene-WS2 Heterostructures for flexible and transparent electronics
• Emergence of Superlattice Dirac Points in Graphene on Hexagonal Boron Nitride
• Cross-sectional imaging of individual layers and buried interfaces of graphene-based heterostructures and superlattices
• First direct observation of Dirac fermions in graphite
• Colloquium: Graphene spectroscopy
• Evidence of Flat Bands and Correlated States in Buckled Graphene Superlattices
• Hierarchy of Hofstadter states and replica quantum Hall ferromagnetism in graphene superlattices
• Conventional Superconductivity in Type II Dirac Semimetal PdTe${}_2$
• The effects of Moire lattice on the electronic properties of graphene

Cited by in corpus (6)

• High-order Van Hove singularities and their connection to flat bands
• Chiral model of twisted bilayer graphene realized in a monolayer
• Kagome and honeycomb flat bands in moiré graphene
• Quantum simulation of honeycomb lattice model by high-order moiré pattern
• Sliding Luttinger Liquid and Topological Flat Bands in Symmetry Mismatched Moiré Interfaces
• Resonant interlayer coupling in NbSe${}_2$-graphite epitaxial moir{é} superlattices