Observation of drastic electronic structure change in one-dimensional moir\'e crystals

TL;DR

This study provides the first experimental evidence of strong intertube coupling effects in one-dimensional moiré superlattices formed by double-wall carbon nanotubes, revealing significant changes in optical spectra due to moiré pattern formation.

Contribution

It demonstrates the first direct experimental observation of drastic electronic structure changes caused by moiré superlattices in one-dimensional nanotube systems.

Findings

Observation of a drastic change in optical transition spectra in specific DWCNTs

Correlation of spectral changes with strong intertube coupling effects

Numerical simulations support experimental results

Abstract

We report the first experimental observation of strong coupling effect in one-dimensional moir\'e crystals. We study one-dimensional double-wall carbon nanotubes (DWCNTs) in which van der Waals-coupled two single nanotubes form one-dimensional moir\'e superlattice. We experimentally combine Rayleigh scattering spectroscopy and electron beam diffraction on the same individual DWCNTs to probe the optical transitions of structure-identified DWCNTs in the visible spectral range. Among more than 30 structure-identified DWCNTs examined, we experimentally observed and identified a drastic change of optical transition spectrum in DWCNT with chirality (12,11)@(17,16). The origin of the marked change is attributed to the strong intertube coupling effect in a moir\'e superlattice formed by two nearly-armchair nanotubes. Our numerical simulation is consistent to these experimental findings.