Twist-controlled resonant tunnelling between monolayer and bilayer graphene

Lane, Thomas; Wallbank, John

doi:10.1063/1.4935988

Cited by 19 publications

(24 citation statements)

References 31 publications

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“…We attribute this to a large twist angle (≈ 5º) which shifts VHS to above 0.4 eV, higher than the chemical potential (~ 0.2 eV) in tBGr we can reach by applying gate and bias voltages. ) with modified electrostatic model considering AB stacking bilayer graphene as the top electrode [25]:…”

Section: Resultsmentioning

confidence: 99%

Stacking transition in bilayer graphene caused by thermally activated rotation

et al. 2016

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Crystallographic alignment between two-dimensional crystals in van der Waals heterostructures brought a number of profound physical phenomena, including observation of Hofstadter butterfly and topological currents, and promising novel applications, such as resonant tunnelling transistors. Here, byprobing the electronic density of states in graphene using graphene-hexagonal boron nitride tunnelling transistors, we demonstrate a structural transition of bilayer graphene from incommensurate twisted stacking state into a commensurate AB stacking due to a macroscopic graphene self-rotation. This structural transition is accompanied by a topological transition in the reciprocal space and by pseudospin texturing.The stacking transition is driven by van der Waals interaction energy of the two graphene layers and is thermally activated by unpinning the microscopic chemical adsorbents which are then removed by the selfcleaning of graphene.

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Section: Resultsmentioning

confidence: 99%

Stacking transition in bilayer graphene caused by thermally activated rotation

et al. 2016

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“…In the case of graphene, studies of its role as a barrier in magnetic tunnel junctions [35][36][37] and between metal contacts [38,39] showed that it behaves as a strong out-of-plane insulator. In fact, in experiments conducted in the absence of a magnetic field and in the presence of a field parallel to the graphene layers, the measured tunnelling current has been well described by assuming that all tunnelling from the further BLG layer is suppressed [10,12]. For this reason, here, we take the limit c = c, corresponding to the decay through graphene being significant and similar to that through hexagonal boron nitride.…”

Section: Device Description and Tunnelling Matrix Elementmentioning

confidence: 99%

Valley-polarized tunneling currents in bilayer graphene tunneling transistors

2019

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We study theoretically the electron current across a monolayer graphene/hexagonal boron nitride/bilayer graphene tunnelling junction in an external magnetic field perpendicular to the layers. We show that change in effective tunnelling barrier width for electrons on different graphene layers of bilayer graphene, coupled with the fact that its Landau level wave functions are not equally distributed amongst the layers with a distribution that is reversed between the two valleys, lead to valley polarisation of the tunnelling current. We estimate that valley polarisation ∼ 70% can be achieved in high quality devices at B = 1 T. Moreover, we demonstrate that strong valley polarisation can be obtained both in the limit of strong-momentum conserving tunnelling and in lower quality devices where this constraint is lifted. * J.J.P. Thompson@bath.ac.uk FIG. 1. (Color online) Schematic of the tunnelling device discussed here. Also shown are the tuning potentials V b , Vg and Vt and direction of the applied magnetic field B.arXiv:1811.04687v2 [cond-mat.mes-hall]

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“…Gr/BN/Gr structures display negative differential resistance (NDR), 20,24,27,[30][31][32]34 and theoretical calculations predict maximum frequencies of several hundred GHz. 26 The NDR arises from the line-up of the source and drain graphene Dirac cones combined with the conservation of in-plane momentum.…”

Section: Introductionmentioning

confidence: 99%

“…In one experiment in which plateaus were observed in the current-voltage characteristics instead of NDR, the experimental results could be matched theoretically by ignoring momentum conservation. 23 In the theoretical treatments, the focus has been primarily on the rotation between top and bottom graphene layers and the resulting misalignment of the Dirac cones 20,27,32 . Recently, the effect of misalignment of both the BN and the graphene layers including the effects of phonon scattering have been investigated using the low-angle effective continuum model 30,35 .…”

Section: Introductionmentioning

confidence: 99%

“…There is also significant interest in Gr/BN/Gr heterostructures for electronic device applications [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] . Gr/BN/Gr structures display negative differential resistance (NDR), 20,24,27,[30][31][32]34 and theoretical calculations predict maximum frequencies of several hundred GHz.…”

Section: Introductionmentioning

confidence: 99%

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Interlayer transport through a graphene/rotated boron nitride/graphene heterostructure

Habib

et al. 2017

Phys. Rev. B

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Interlayer electron transport through a graphene / hexagonal boron-nitride (h-BN) / graphene heterostructure is strongly affected by the misorientation angle θ of the h-BN with respect to the graphene layers with different physical mechanisms governing the transport in different regimes of angle, Fermi level, and bias. The different mechanisms and their resulting signatures in resistance and current are analyzed using two different models, a tight-binding, non-equilibrium Green function model and an effective continuum model, and the qualitative features resulting from the two different models compare well. In the large-angle regime (θ > 4• ), the change in the effective h-BN bandgap seen by an electron at the K point of the graphene causes the resistance to monotonically increase with angle by several orders of magnitude reaching a maximum at θ = 30• . It does not affect the peak-to-valley current ratios in devices that exhibit negative differential resistance. In the small-angle regime (θ < 4• ), Umklapp processes open up new conductance channels that manifest themselves as non-monotonic features in a plot of resistance versus Fermi level that can serve as experimental signatures of this effect. For small angles and high bias, the Umklapp processes give rise to two new current peaks on either side of the direct tunneling peak.

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Twist-controlled resonant tunnelling between monolayer and bilayer graphene

Cited by 19 publications

References 31 publications

Stacking transition in bilayer graphene caused by thermally activated rotation

Stacking transition in bilayer graphene caused by thermally activated rotation

Valley-polarized tunneling currents in bilayer graphene tunneling transistors

Interlayer transport through a graphene/rotated boron nitride/graphene heterostructure

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