One-dimensional flat bands in twisted bilayer germanium selenide

Kennes, Dante M.; Xian, Lede; Claassen, Martin; Rubio, Ángel

doi:10.1038/s41467-020-14947-0

Cited by 115 publications

(97 citation statements)

References 55 publications

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“…The stacking energy function is widely used for modeling twisted multilayers across a broad range of twist angles and strain conditions, and has direct implications for the electronic band-structure 40 . Moiré metrology is not restricted to the discussed material systems and can be universally applied with other systems of great current interest 41 – 48 . Therefore, by providing a reliable account of the stacking energy function, moiré metrology has a broad impact across the field of vdW heterostructures.…”

Section: Discussionmentioning

confidence: 99%

Moiré metrology of energy landscapes in van der Waals heterostructures

et al. 2021

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The emerging field of twistronics, which harnesses the twist angle between two-dimensional materials, represents a promising route for the design of quantum materials, as the twist-angle-induced superlattices offer means to control topology and strong correlations. At the small twist limit, and particularly under strain, as atomic relaxation prevails, the emergent moiré superlattice encodes elusive insights into the local interlayer interaction. Here we introduce moiré metrology as a combined experiment-theory framework to probe the stacking energy landscape of bilayer structures at the 0.1 meV/atom scale, outperforming the gold-standard of quantum chemistry. Through studying the shapes of moiré domains with numerous nano-imaging techniques, and correlating with multi-scale modelling, we assess and refine first-principle models for the interlayer interaction. We document the prowess of moiré metrology for three representative twisted systems: bilayer graphene, double bilayer graphene and H-stacked MoSe2/WSe2. Moiré metrology establishes sought after experimental benchmarks for interlayer interaction, thus enabling accurate modelling of twisted multilayers.

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Section: Discussionmentioning

confidence: 99%

Moiré metrology of energy landscapes in van der Waals heterostructures

et al. 2021

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“…After the first experimental findings [1,2], twisted bilayer graphene (TBG) has been the subject of intense investigation from both an experimental and theoretical point of view. When the rotation angle between the two graphene layers is close to the first "magic angle," θ ∼ 1.08 • , transport experiments show different superconducting domes as well as correlated insulating phases [3][4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Structural relaxation and low-energy properties of twisted bilayer graphene

Cantele

Conte

Cataudella

et al. 2020

Phys. Rev. Research

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The structural and electronic properties of twisted bilayer graphene are investigated from first-principles and tight-binding approach as a function of the twist angle (ranging from the first "magic" angle θ = 1.08 • to θ = 13.17 • , with the former corresponding to the largest unit cell, comprising 11,164 carbon atoms). By properly taking into account the long-range van der Waals (vdW) interaction, we provide the patterns for the atomic displacements (with respect to the ideal twisted bilayer). The out-of-plane relaxation shows an oscillating ("buckling") behavior, very evident for the smallest angles, with the atoms around the AA stacking regions interested by the largest displacements. The out-of-plane displacements are accompanied by a significant in-plane relaxation, showing a vortexlike pattern, where the vorticity (intended as curl of the displacement field) is reverted when moving from the top to the bottom plane and vice versa. Overall, the atomic relaxation results in the shrinking of the AA stacking regions in favor of the more energetically favorable AB/BA stacking domains. The measured flat bands emerging at the first magic angle can be accurately described only if the atomic relaxations are taken into account. Quite importantly, the experimental gaps separating the flat-band manifold from the higher and lower energy bands are intimately related to out-of-plane relaxations. The stability of the relaxed bilayer at the first magic angle is estimated to be of the order of 0.5-0.9 meV per atom (or 7-10 K). Our calculations shed light on the importance of an accurate description of the vdW interaction and of the resulting atomic relaxation to envisage the electronic structure of this really peculiar kind of vdW bilayers.

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“…Therefore the IHM can be considered as a canonical model to study the nature of transition between band and Mott insulating phases of matter. Furthermore, in the light of recent cold atom realization of IHM and the invention of superlattice modulation spectroscopy to probe the bond order, and a very appealing recent proposal to realized 1D IHM in twisted bilayer GeSe, the time is ripe to investigate the quantum integrability of this model which will hopefully pave the path for the construction of a possible exact solution.…”

Section: Introductionmentioning

confidence: 99%

Quantum Integrability of 1D Ionic Hubbard Model

Hosseinzadeh

Jafari

2020

Annalen der Physik

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The quantum integrability of the 1D ionic Hubbard model (IHM) is established using two independent numerical methods, namely i) energy level spacing statistics and ii) occupation profile of one‐particle density matrix (OPDM) eigen‐values. Both methods suggest that the 1D IHM is integrable. The calculations of energy level statistics reproduce the known results for the standard Hubbard model. Upon turning on the the ionic term, the energy level spacing distribution of this model continues to obey the Poissonian distribution. Occupation patterns as extracted from OPDM indicate that quasi‐particles are sharpened upon increasing the ionic potential. This is evidenced by a larger jump in the occupation number distribution.

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One-dimensional flat bands in twisted bilayer germanium selenide

Cited by 115 publications

References 55 publications

Moiré metrology of energy landscapes in van der Waals heterostructures

Moiré metrology of energy landscapes in van der Waals heterostructures

Structural relaxation and low-energy properties of twisted bilayer graphene

Quantum Integrability of 1D Ionic Hubbard Model

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