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arXiv · 2109.00718

The Effect of Twisting Angle on the Electronic Properties and Electron Transport and Hall Effect in the Twisted Circular and Rectangular Graphene and Graphene/Boron-Nitride Channels

Farzaneh Shayeganfar·Ali Ramazani·Nicholas X Fang
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Abstract

Twisted bilayer graphene (tBLG) including interlayer interaction and rotational disorder shows anomalous electron transport as a function of twist-angles (tAs). In this work, we address the electronic properties and electron transport of circular and rectangular twisted graphene nanoribbon (tGN) and twisted heterostructure of graphene/boron-nitride nanoribbon (thG/BNN) channels by applying the tight-binding Hamiltonian for two regimes of small and large tAs. Analysis of band structure reveals that the circular tGNs for small and large tAs have metallic behavior, while phase transition of metal to semiconductor occurs in rectangular case, sweeping small tAs to large ones. This implies a different transport mechanism depending on the tAs disorder, whiles the Klein paradox appears in the transmission and conductance of circular tGNs. We distinguish that the local electron states of rectangular tGNs with large tAs create degenerate multiflat bands, supporting decoupling of two ribbons and high conductance state. However, coupled two Dirac electron gases for small tAs of rectangular channel cause Klein paradox due to their resonant scattering. We compute the Hall conductivity in both tGNs for wide range of magnetic field. In circular tGNs the valance and conduction band energy is quantized into electron/hole-like Landau level, while for rectangular tGNs with applied magnetic field the Hall conductivity shows complex behavior. Moreover, we provide a platform for quantum transport and Hall effect of thG/BNN, which host a vast nontrivial emergent electronic state. Our findings suggest that circular/rectangular tGNs and thG/BNNs with new electron states of Moiré pattern besides the Klein paradox suitable for switching of several nanochannel.

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Farzaneh Shayeganfar, Ali Ramazani, Nicholas X Fang. 2023-06-11. The Effect of Twisting Angle on the Electronic Properties and Electron Transport and Hall Effect in the Twisted Circular and Rectangular Graphene and Graphene/Boron-Nitride Channels. https://arxiv.org/abs/2109.00718

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