High-order minibands and interband Landau level reconstruction in graphene moire superlattice

Abstract

The propagation of Dirac fermions in graphene through a long-period periodic potential would result in a band folding together with the emergence of a series of cloned Dirac points (DPs). In highly aligned graphene/hexagonal boron nitride (G/hBN) heterostructures, the lattice mismatch between the two atomic crystals generates a unique kind of periodic structure known as a moiré superlattice. Of particular interests is the emergent phenomena related to the reconstructed band-structure of graphene, such as the Hofstadter butterfly, topological currents, gate dependent pseudospin mixing, and ballistic miniband conduction. However, most studies so far have been limited to the lower-order minibands, e.g. the 1st and 2nd minibands counted from charge neutrality, and consequently the fundamental nature of the reconstructed higher-order miniband spectra still remains largely unknown. Here we report on probing the higher-order minibands of precisely aligned graphene moiré superlattices by transport spectroscopy. Using dual electrostatic gating, the edges of these high-order minibands, i.e. the 3rd and 4th minibands, can be reached. Interestingly, we have observed interband Landau level (LL) crossinginducing gap closures in a multiband magneto-transport regime, which originates from band overlap between the 2nd and 3rd minibands. As observed high-order minibands and LL reconstruction qualitatively match our simulated results. Our findings highlight the synergistic effect of minibands in transport, thus presenting a new opportunity for graphene electronic devices.

References in corpus (7)

• Emergence of Superlattice Dirac Points in Graphene on Hexagonal Boron Nitride
• Detecting Topological Currents in Graphene Superlattices
• Anisotropic behaviors of massless Dirac fermions in graphene under periodic potential
• New Generation of Massless Dirac Fermions in Graphene under External Periodic Potentials
• Quantum Hall effect and Landau level crossing of Dirac fermions in trilayer graphene
• Zero Energy Modes and Gate-Tunable Gap in Graphene on hexagonal Boron Nitride
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Cited by in corpus (6)

• Hofstadter Topology with Real Space Invariants and Reentrant Projective Symmetries
• Higher-order Bragg gaps in the electronic band structure of bilayer graphene renormalized by recursive supermoiré potential
• Transport evidence of superlattice Dirac cones in graphene monolayer on twisted boron nitride substrate
• High-mobility compensated semimetals, orbital magnetization, and umklapp scattering in bilayer graphene moire superlattices
• Electric field tunable bands in doubly aligned bilayer graphene hBN moire superlattice
• Hofstadter Butterfly in Graphene