Band structure engineering of 2D materials using patterned dielectric superlattices.
Carlos Forsythe,Xiaodong Zhou,Xiaodong Zhou,Kenji Watanabe,Takashi Taniguchi,Abhay Pasupathy,Pilkyung Moon,Mikito Koshino,Philip Kim,Cory Dean +9 more
TLDR
In this article, a new approach to fabricate high-mobility superlattice devices by integrating surface dielectric patterning with atomically thin van der Waals materials is presented.Abstract:
The ability to manipulate electrons in two-dimensional materials with external electric fields provides a route to synthetic band engineering. By imposing artificially designed and spatially periodic superlattice potentials, electronic properties can be further altered beyond the constraints of naturally occurring atomic crystals1–5. Here, we report a new approach to fabricate high-mobility superlattice devices by integrating surface dielectric patterning with atomically thin van der Waals materials. By separating the device assembly and superlattice fabrication processes, we address the intractable trade-off between device processing and mobility degradation that constrains superlattice engineering in conventional systems. The improved electrostatics of atomically thin materials allows smaller wavelength superlattice patterns relative to previous demonstrations. Moreover, we observe the formation of replica Dirac cones in ballistic graphene devices with sub-40 nm wavelength superlattices and report fractal Hofstadter spectra6–8 under large magnetic fields from superlattices with designed lattice symmetries that differ from that of the host crystal. Our results establish a robust and versatile technique for band structure engineering of graphene and related van der Waals materials with dynamic tunability. A new superlattice fabrication process on 2D material heterostructures enables the observation of replica Dirac cones in graphene as well as Hofstadter’s fractal magnetic spectrum under triangular and square superlattice symmetries.read more
Citations
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Disorder in van der Waals heterostructures of 2D materials
TL;DR: The progress in disorder control for graphene and TMDs is discussed, as well as in van der Waals heterostructures realized by combining these materials with hexagonal boron nitride.
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Electronic-structure methods for twisted moiré layers
TL;DR: When single layers of 2D materials are stacked on top of one another with a small twist in orientation, the resulting structure often involves incommensurate moire patterns as mentioned in this paper.
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Electron quantum metamaterials in van der Waals heterostructures.
TL;DR: This Perspective highlights the intriguing potential of designer structuring of electronic matter at scales at and below the electron wavelength, which affords a new range of synthetic quantum metamaterials with unconventional responses.
Journal ArticleDOI
Tunable crystal symmetry in graphene-boron nitride heterostructures with coexisting moiré superlattices.
Nathan Finney,Matthew Yankowitz,Lithurshanaa Muraleetharan,Kenji Watanabe,T. Taniguchi,Cory Dean,James Hone +6 more
TL;DR: The results demonstrate that the interplay between multiple moiré patterns can be utilized to controllably modify the symmetry and electronic properties of the composite heterostructure, enabling tunable crystal symmetry and strong modification of the graphene band structure.
Journal ArticleDOI
New Generation of Moiré Superlattices in Doubly Aligned hBN/Graphene/hBN Heterostructures.
Lujun Wang,Simon Zihlmann,Ming-Hao Liu,Péter Makk,Péter Makk,Kenji Watanabe,Takashi Taniguchi,Andreas Baumgartner,Christian Schönenberger +8 more
TL;DR: In this article, the authors reported a moire superlattice in fully hBN encapsulated graphene with both the top and the bottom hBN aligned to the graphene and showed that the overlay of two different moires can result in a third moire with a period larger than the maximum period (14 nm).
References
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