Interlayer Interactions in 1D Van der Waals Moiré Superlattices

Abstract

Studying two‐dimensional (2D) van der Waals (vdW) moiré superlattices and their interlayer interactions have received surging attention after recent discoveries of many new phases of matter that are highly tunable. Different atomistic registry between layers forming the inner and outer nanotubes can also form one‐dimensional (1D) vdW moiré superlattices. In this review, experimental observations and theoretical perspectives related to interlayer interactions in 1D vdW moiré superlattices are summarized. The discussion focuses on double‐walled carbon nanotubes (DWNTs), a model 1D vdW moiré system, and the authors highlight the new optical features emerging from the non‐trivial strong interlayer coupling effect and the unique physics in 1D DWNTs. Future directions and questions in probing the intriguing physical phenomena in 1D vdW moiré superlattices such as, correlated physics in different 1D moiré systems beyond DWNTs are proposed and discussed.

Observation of Moiré Patterns in Twisted Stacks of Bilayer Perovskite Oxide Nanomembranes with Various Lattice Symmetries

“…Such patterns have been visualized by various techniques showcasing hexagon-like novel paradigm materials platform with tunable lattice parameters . In addition to 2D materials, 1D vdW moiré superlattices in carbon nanotubes and 3D moiré superlattices in thick hBN film have also been demonstrated. The presence of moiré pattern is not only seen in hexagonal-lattice-based 2D materials but also shown in mechanically exfoliated layered perovskite-derived oxides, such as Bi 2 Sr 2 CaCu 2 O 8+ x …”

One-Dimensional Moiré Superlattices and Flat Bands in Collapsed Chiral Carbon Nanotubes

“…The quest for novel materials which could enlighten these new phenomena has even extended to onedimensional systems, where many-body effects have been widely described. Flat bands can be found in some onedimensional materials [13][14][15][16]; for instance, carbon nanotubes (CNTs) can show moiré patterns in their doublewalled and multi-walled form [17][18][19], and single-walled tubes also display moirés when collapsed [15]. For the latter, flat bands with an even smaller energy span than TBG and sharp densities of states ensue along with these one-dimensional patterns.…”

Optically active cross-band transition in double-walled carbon nanotube and its impact on Raman resonances

“…It was also noted that the intertube distance plays a key role, i.e. the shorter the distance, the stronger the interactions [3,11,20]. Recently, a drastic change of the optical transition spectrum in (12,11)@(17,16) DWNT was experimentally observed [17] and explained as resulting of strong interlayer coupling effects as expected from Koshino's criteria in this peculiar DWNT formed by two-nearly armchair SWNTs [10].…”

“…[1] and references therein). Double-walled carbon nanotubes (DWNTs) are often regarded as the simplest onedimensional (1D) van der Waals moiré superlattices, being the ideal structures to explore the interlayer coupling at the nanoscale in 1D systems [2,3]. DWNTs possess a unique two-layer coaxial structure consisting of two nested single-walled carbon nanotubes (SWNTs) bound together by weak van der Waals interactions.…”

“…DWNTs possess a unique two-layer coaxial structure consisting of two nested single-walled carbon nanotubes (SWNTs) bound together by weak van der Waals interactions. Indeed the electronic, mechanical, optical and vibrational properties of DWNTs are not only inherited from their SWNTs building blocks but also result from interlayer interactions [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21].…”