Experimental evidence for non-Abelian gauge potentials in twisted graphene bilayers

Yin, Long-Jing; Qiao, Jia-Bin; Zuo, Wei-Jie; Li, Wen-Tian; He, Lin

doi:10.1103/physrevb.92.081406

Cited by 77 publications

(91 citation statements)

References 29 publications

(78 reference statements)

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“…This similarity may support the interpretation of the twisted interlayer interaction as a non-abelian gauge field, the exact nature of which is still being investigated 26,32,36,37 . These calculations allow a very robust determination of the monolayer's Fermi velocity without a band-structure calculation, using the low-energy model for the LL's 28 :…”

Section: Bilayer Graphenementioning

confidence: 58%

“…These hybridizations at the overlap of the Dirac cones produce the VHS 28 , which have already been investigated by experimental STM measurements [29][30][31][32] .…”

Section: Bilayer Graphenementioning

confidence: 99%

“…1 we compare the spatial dependence of tBLG at four twist angles to experimental results 32 . This is possible because sampling shifts over the diagonal of one layer's unit-cell is the same as moving linearly from an AA to AB type stacking in the real-space moiré pattern.…”

Section: Bilayer Graphenementioning

confidence: 99%

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Twistronics: Manipulating the electronic properties of two-dimensional layered structures through their twist angle

et al. 2017

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The ability in experiments to control the relative twist angle between successive layers in twodimensional (2D) materials offers a new approach to manipulating their electronic properties; we refer to this approach as "twistronics". A major challenge to theory is that, for arbitrary twist angles, the resulting structure involves incommensurate (aperiodic) 2D lattices. Here, we present a general method for the calculation of the electronic density of states of aperiodic 2D layered materials, using parameter-free hamiltonians derived from ab initio density-functional theory. We use graphene, a semimetal, and MoS2, a representative of the transition metal dichalcogenide (TMDC) family of 2D semiconductors, to illustrate the application of our method, which enables fast and efficient simulation of multi-layered stacks in the presence of local disorder and external fields. We comment on the interesting features of their Density of States (DoS) as a function of twist-angle and local configuration and on how these features can be experimentally observed.

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Section: Bilayer Graphenementioning

confidence: 58%

“…These hybridizations at the overlap of the Dirac cones produce the VHS 28 , which have already been investigated by experimental STM measurements [29][30][31][32] .…”

Section: Bilayer Graphenementioning

confidence: 99%

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Twistronics: Manipulating the electronic properties of two-dimensional layered structures through their twist angle

et al. 2017

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“…In a follow-up study Yan et al [14] showed the breakdown of van Hove singularities beyond a twist angle of about 3.5 o , indicating that the continuum models are no longer applicable at these relatively large twist angles. Yin et al [15] showed that there is a magic twist angle of 1.11 o at which the two van Hove singularities merge together and form a well-defined peak at the charge neutrality point. In addition to this strong peak at the charge neutrality point these authors also found a set of regularly spaced peaks.…”

Section: Introductionmentioning

confidence: 99%

“…Wong et al [16] found, besides the coexistence of moiré patterns and moiré super-superlattices, also a very rich an interesting electronic structure. Despite the fact that the electronic structure of twisted bilayer graphene has been extensively studied [5,[11][12][13][14][15][16][17][18][19][20][21][22][23][24], the spatial variation of electronic structure within the unit cell of the moiré pattern did not receive a lot of attention yet.…”

Section: Introductionmentioning

confidence: 99%

Spatially resolved electronic structure of twisted graphene

Yao

Bremen

Slotman³

et al. 2017

Phys. Rev. B

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We have used scanning tunneling microscopy and spectroscopy to resolve the spatial variation of the density of states of twisted graphene layers on top of a highly oriented pyrolytic graphite substrate. Owing to the twist a moire pattern develops with a periodicity that is substantially larger than the periodicity of a single layer graphene. The twisted graphene layer has electronic properties that are distinctly different from that of a single layer graphene due to the nonzero interlayer coupling. For small twist angles (about 1-3.5 degree) the integrated differential conductivity spectrum exhibits two well-defined Van Hove singularities. Spatial maps of the differential conductivity that are recorded at energies near the Fermi level exhibit a honeycomb structure that is comprised of two inequivalent hexagonal sub-lattices. For energies |E-E_F|>0.3 eV the hexagonal structure in the differential conductivity maps vanishes. We have performed tight-binding calculations of the twisted graphene system using the propagation method, in which a third graphene layer is added to mimic the substrate. This third layer lowers the symmetry and explains the development of the two hexagonal sub-lattices in the moire pattern. Our experimental results are in excellent agreement with the tight-binding calculations.Comment: To appear in Phys. Rev.

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