Anisotropic band flattening in graphene with one-dimensional superlattices

Li, Yutao; Dietrich, Scott; Forsythe, Carlos; Taniguchi, Takashi; Watanabe, Kenji; Moon, Pilkyung; Dean, Cory

doi:10.1038/s41565-021-00849-9

Cited by 69 publications

(63 citation statements)

References 37 publications

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“…Superlattice potentials are known to increase the number of Dirac points of graphene [16][17][18][21][22][23][24]26 and as such introduce new physical modes at zero energy, as recently observed in Ref. [25]. Some relevant applications originated from the periodic structures are electron beam supercollimation and electron wave filter 24,26 .…”

Section: Introductionmentioning

confidence: 90%

Band-gap formation and morphing in α−T3 superlattices

et al. 2021

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Electrons in α − T3 lattices behave as condensed-matter analogies of integer-spin Dirac Fermions. The three atoms making up the unit cell bestow the energy spectrum with an additional energy band that is completely flat, providing unique electronic properties. The interatomic hopping term, α, is known to strongly affect the electronic spectrum of the 2D lattice, allowing it to continuously morph from graphene-like responses to the behaviour of Fermions in a Dice lattice. For pristine lattice structures, the energy bands are gapless, however small deviations in the atomic equivalence of the three sublattices will introduce gaps in the spectrum. It is unknown how these affect transport and electronic properties such as the energy spectrum of superlattice mini-bands. Here we investigate the dependency of these properties on the parameter α accounting for different symmetry-breaking terms and show how it affects band gap formation. Furthermore, we find that superlattices can force band gaps to close and shift in energy. Our results demonstrate that α − T3 superlattices provide a versatile material for 2D band gap engineering purposes.

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Section: Introductionmentioning

confidence: 90%

Band-gap formation and morphing in α−T3 superlattices

et al. 2021

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“…The checkerboard potential, a member of wallpaper group 11 (p4mm), pictured in Figure 4, is used as an extension of the 1D case of a square potential as investigated by Li and colleagues [18], as it is composed of The amplitude is measured in units of t, the velocity is measured relative to the Fermi velocity of electrons in graphene, v f , and the inverse mass is measured in units of t • A, where A is the extended unit cell area.…”

Section: A Checkerboard Potentialmentioning

confidence: 99%

“…It has previously been predicted that applying a potential with periodicity in one direction to graphene would induce band flattening in one direction [16]. More recently, this asymmetric band flattening was realized experimentally in graphene [17,18]. In particular, it has been shown that band flattening can be induced, for instance, in the k x direction alone by applying a square wave potential along the y spatial direction.…”

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confidence: 96%

Theory of engineering flat bands in graphene using doubly-periodic electrostatic gating

Hougland¹,

Ramachandran²,

Levy³

et al. 2021

Preprint

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We explore the use of applied electrical potentials to induce band flattening in graphene for bands near zero energy. We consider various families of doubly periodic potentials and simulate their effect on the electronic band structure using a tight-binding and a continuum approach. From these families, we find that an applied potential with symmetries of wallpaper group 17, in particular a Kagome potential, works best for inducing a high degree of band flattening for a range of realistic potential amplitudes and periods. Our work indicates that it should be possible to engineer the band structure of graphene using electrostatic gating, thus enabling a new approach to the development of graphene-based metamaterials.

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“…With the advent of two-dimensional (2D) and atomically thin materials [8][9][10][11], those ideas were swiftly transferred to this arena as well, leading to the realization of 2D superlattices that incorporated not only vertical stacks, but also laterally assembled heterostructures [12][13][14][15][16][17], as well as electrically modulated graphene [18,19], artificial graphene [20,21], and optical near-field dressing through periodic patterning of the supporting dielectric substrate [22]. More recently, similar band structure engineering concepts have been explored to create moiré superlattices [12,[23][24][25][26] and moiré excitons [27][28][29], and also to investigate topological phenomena [30][31][32][33].…”

Section: Introductionmentioning

confidence: 99%

Quantum-phase two-dimensional materials

Giulio¹,

Gonçalves²,

Abajo³

2022

Preprint

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The modification of electronic band structures and the subsequent tuning of electrical, optical, and thermal material properties is a central theme in the engineering and fundamental understanding of solid-state systems. In this scenario, atomically thin materials offer an appealing platform because they are extremely susceptible to electric and magnetic gating, as well as to interlayer hybridization in stacked configurations, providing the means to customize and actively modulate their response functions. Here, we introduce a radically different approach to material engineering relying on the self-interaction that electrons in a two-dimensional material experience when an electrically neutral structure is placed in its vicinity. Employing rigorous theoretical methods, we show that electrons in a semiconductor atomic monolayer acquire a quantum phase resulting from the image potential induced by the presence of a neighboring periodic array of conducting ribbons, which in turn produces strong modifications in the optical, electrical, and thermal properties of the monolayer, specifically giving rise to the emergence of interband optical absorption, plasmon hybridization, and metal-insulator transitions. Beyond its fundamental interest, material engineering based on the quantum phase induced by noncontact neighboring structures represents a disruptive approach to tailor the properties of atomic layers for application in nanodevices.

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Anisotropic band flattening in graphene with one-dimensional superlattices

Cited by 69 publications

References 37 publications

Band-gap formation and morphing in α−T3 superlattices

Band-gap formation and morphing in α−T3 superlattices

Theory of engineering flat bands in graphene using doubly-periodic electrostatic gating

Quantum-phase two-dimensional materials

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