Moiré edge states in twisted graphene nanoribbons

Abstract

The edge physics of graphene based systems is well known to be highly sensitive to the atomic structure at the boundary, with localized zero mode edge states found only on the zigzag type termination of the lattice. Here we demonstrate that the graphene twist bilayer supports an additional class of edge states, that (i) are found for all edge geometries and thus are robust against edge roughness, (ii) occur at energies coinciding with twist induced van Hove singularities in the bulk and (iii) possess an electron density strongly modulated by the moiré lattice. Interestingly, these "moiré edge states" exist only for certain lattice commensurations and thus the edge physics of the twist bilayer is, in dramatic contrast to that of the bulk, not uniquely determined by the twist angle. arXiv:1801.06464v1 [cond-mat.mes-hall]

Electrically Tunable Gauge Fields in Tiny-Angle Twisted Bilayer Graphene

“…Introducing one extra layer of complexity, twisted bilayer graphene (TBG) is known to host a plethora of new interesting phenomena [20][21][22][23][24][25][26][27][28][29][30], stemming from the appearance of a new scale: the Moiré length L M [31][32][33][34][35][36][37]. The physics of TBG strongly depends on the angle α between the two layers.…”

Controlling Surface States of Planar Metamaterial Based on Moire Effect

“…2), the depth of the stop band gap also increases. This is easily can be explained by the fact that with an increase in the period of the second PC, the quasi-period decreases according to formula (1), and at a fixed length of the resulting moire metamaterial the number of such quasi-periods increases also. And as is well known, the depth of the stop band of a spatially bounded photonic crystal is in the first approximation proportional to this number.…”

“…It can be seen from (1), that if the difference in the periods of forming photonic crystals becomes smaller, then the quasi-period becomes larger. Thus, it is possible to choose the periods of subwavelength PCs in such a way that the quasi-period of the obtained moire metamaterial approximately corresponds to one or several half-wavelengths at the selected frequency.…”

Circular quantum dots in twisted bilayer graphene

“…In this study the obtained energy levels are highly influenced by the edge effects of the flakes. The electronic [46][47][48] and transport 49,50 properties of tBLG nanoribbons have also been investigated, in which the transport properties of the low-energy regime were determined by the interplay between the moiré pattern and the tBLG edges 49 . Another study was devoted to the investigation of the electronic properties of tBLG flakes with irregular shapes 51 .…”