Accurate Measurement of the Gap of Graphene/hBN Moiré Superlattice through Photocurrent Spectroscopy
arXiv:2103.08120 · doi:10.1103/PhysRevLett.126.146402
Abstract
Monolayer graphene aligned with hexagonal boron nitride (hBN) develops a gap at the charge neutrality point (CNP). This gap has previously been extensively studied by electrical transport through thermal activation measurements. Here, we report the determination of the gap size at the CNP of graphene/hBN superlattice through photocurrent spectroscopy study. We demonstrate two distinct measurement approaches to extract the gap size. A maximum of ~ 14 meV gap is observed for devices with a twist angle of less than 1 degree. This value is significantly smaller than that obtained from thermal activation measurements, yet larger than the theoretically predicted single-particle gap. Our results suggest that lattice relaxation and moderate electron-electron interaction effects may enhance the CNP gap in hBN/graphene superlattice.
6 pages, 4 figures
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Cited by in corpus (8)
- Photocurrent as a multi-physics diagnostic of quantum materials
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- Milli-Tesla Quantization enabled by Tuneable Coulomb Screening in Large-Angle Twisted Graphene
- Chiral transport of hot carriers in graphene in the quantum Hall regime
- Insulators at Fractional Fillings in Twisted Bilayer Graphene Partially Aligned to Hexagonal Boron Nitride
- Unveiling the Miniband Structure of Graphene Moiré Superlattices via Gate-dependent Terahertz Photocurrent Spectroscopy
- Strongly Coupled Exciton--Hyperbolic-phonon-polariton Hybridized States in hBN-encapsulated Biased Bilayer Graphene
- Effect of Uncorrelated On-site Scalar Potential and Mass Disorder on Transport of Two-Dimensional Dirac Fermions