Hall effects in artificially corrugated bilayer graphene without breaking time-reversal symmetry

Ho, Sheng Chin; Chang, Ching Hao; Hsieh, Yu Chiang; Lo, Shun‐Tsung; Huang, Bo; Vu, Thi Hai Yen; Ortix, Carmine; Chen, Tse-Ming

doi:10.1038/s41928-021-00537-5

Cited by 81 publications

(60 citation statements)

References 55 publications

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“…The amplitude of the wrinkles increase with strain as the crack propagates in the direction of the crack length until the material fractures at a strain of 0.022 (d). This trend of strain-correlated corrugation was also observed in monolayer and bilayer graphene, and has been demonstrated to influence their electronic and chemical properties [52][53][54][55]. The same fracture mechanism is observed in all the other samples tested consisting of different crack lengths, system sizes and strain rates.…”

Section: Fracture Toughnesssupporting

confidence: 67%

Atomic Insights into Fracture Characteristics of Twisted Tri-Layer Graphene

2021

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Graphene twistronics have recently gained significant attention due their superconductive behavior as a consequence of their tunable electronic properties. Although the electronic properties of twisted graphene have been extensively studied, the mechanical properties and integrity of twisted trilayer graphene (tTLG) under loading is still elusive. We investigated the fracture mechanics of tTLG with a twist angle of ±1.53° utilizing molecular dynamics simulation. This twist angle was chosen because it is known to exhibit highly superconductive behavior. The results indicate that tTLG does not preserve the excellent mechanical properties typically associated with graphene, with toughness and fracture strain values much lower in comparison. The Young’s modulus was an exception with values relatively close to pristine graphene, whereas the tensile strength was found to be roughly half of the intrinsic strength of graphene. The fracture toughness, fracture strain and strength converge as the crack length increases, reaching 0.26 J/m3, 0.0217 and 39.9 GPa at a crack length of 8 nm, respectively. The Griffth critical strain energy is 19.98 J/m2 and the critical stress intensity factor Kc is 4.47 MPa M1/2, in good agreement with that of monolayer graphene in the experiment. Our atomic insights might be helpful in the material design of twisted trilayer graphene-based electronics.

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Section: Fracture Toughnesssupporting

confidence: 67%

Atomic Insights into Fracture Characteristics of Twisted Tri-Layer Graphene

2021

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“…The Berry curvature dipole describes the dipole moment of the Berry curvature in momentum space 1 . In addition, the nonlinear Hall effect is a quantum transport phenomenon near the dc limit because of the extremely low frequency (~10 to 1000 Hz) of the input currents in experiments 7,8,[34][35][36][37][38][39][40][41] . The importance of the quantum description of dc quantum transports has been well acknowledged 42 .…”

mentioning

confidence: 99%

Quantum theory of the nonlinear Hall effect

Wang

Sun

et al. 2021

Nat Commun

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The nonlinear Hall effect is an unconventional response, in which a voltage can be driven by two perpendicular currents in the Hall-bar measurement. Unprecedented in the family of the Hall effects, it can survive time-reversal symmetry but is sensitive to the breaking of discrete and crystal symmetries. It is a quantum transport phenomenon that has deep connection with the Berry curvature. However, a full quantum description is still absent. Here we construct a quantum theory of the nonlinear Hall effect by using the diagrammatic technique. Quite different from nonlinear optics, nearly all the diagrams account for the disorder effects, which play decisive role in the electronic transport. After including the disorder contributions in terms of the Feynman diagrams, the total nonlinear Hall conductivity is enhanced but its sign remains unchanged for the 2D tilted Dirac model, compared to the one with only the Berry curvature contribution. We discuss the symmetry of the nonlinear conductivity tensor and predict a pure disorder-induced nonlinear Hall effect for point groups C3, C3h, C3v, D3h, D3 in 2D, and T, Td, C3h, D3h in 3D. This work will be helpful for explorations of the topological physics beyond the linear regime.

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“…Remarkably, dipoles in the tens of nanometer scale have been recently found in the corrugated bilayer graphene nanoarchitectures of ref. [80]. We also note that the conspiracy of strain and warping of the Fermi surface has been shown to yield various features [ 99 ] in the Magnus Hall response [ 100 ] appearing when built‐in electric fields are present.…”

Section: Berry Curvature Dipole In the Absence Of Spin–orbit Couplingmentioning

confidence: 87%

“…Independent of the presence and nature of the external perturbation, the appearance of the time‐reversal symmetric NLHE was originally believed to necessitate a substantial spin–orbit coupling. However, the experimental demonstration of non‐linear transverse currents in strained (bilayer) graphene [ 80 ] has shown that this effect could be also pursued in systems made of light elements, where the presence of spin–orbit coupling could be neglected all together. This has opened new material avenues for studies of the NLHE with time‐reversal symmetry.…”

Section: Discussionmentioning

confidence: 99%

“…[ 79 ] Importantly, experimental signatures of a non‐linear Hall effect with time‐reversal symmetry have been recently found in corrugated bilayer graphene. [ 80 ] As we will discuss below, the origin of the non‐linear Hall effect in graphene does not stem from the Dirac cone shifting mechanism of bilayer WTe 2 . It is instead the warping of the Fermi surface the physical characteristic responsible for the non‐zero value of the BCD.…”

Section: Berry Curvature Dipole In the Absence Of Spin–orbit Couplingmentioning

confidence: 99%

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Nonlinear Hall Effect with Time‐Reversal Symmetry: Theory and Material Realizations

Ortix

2021

Adv Quantum Tech

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The appearance of a Hall conductance necessarily requires breaking of time‐reversal symmetry, either by an external magnetic field or by the internal magnetization of a material. As a second response, however, Hall dissipationless transverse currents can appear even in time‐reversal symmetric conditions provided the material is non‐centrosymmetric. This non‐linear Hall effect has a quantum origin: it is related to the geometric properties of the electronic wavefunctions and encoded in the dipole moment of the Berry curvature. Here, the general theory underpinning this effect is reviewed and various material platforms where non‐linear Hall transverse responses have been found are discussed. On the theoretical front, the link between the non‐linear Hall effect and the Berry curvature dipole is discussed using Boltzmann transport theory. On the material front, different platforms, including topological crystalline insulators, transition metal dichalcogenides, graphene, and Weyl semimetals are reviewed.

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Hall effects in artificially corrugated bilayer graphene without breaking time-reversal symmetry

Cited by 81 publications

References 55 publications

Atomic Insights into Fracture Characteristics of Twisted Tri-Layer Graphene

Atomic Insights into Fracture Characteristics of Twisted Tri-Layer Graphene

Quantum theory of the nonlinear Hall effect

Nonlinear Hall Effect with Time‐Reversal Symmetry: Theory and Material Realizations

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