Atomic-Scale Observation of Moire potential in Twisted Hexagonal Boron Nitride Layers by Electron Microscopy

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Hauptverfasser: Mishima, Rina, Nagai, Takuro, Segawa, Hiroyo, Ehara, Masahiro, Uchino, Takashi
Format: Preprint
Veröffentlicht: 2024
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author Mishima, Rina
Nagai, Takuro
Segawa, Hiroyo
Ehara, Masahiro
Uchino, Takashi
author_facet Mishima, Rina
Nagai, Takuro
Segawa, Hiroyo
Ehara, Masahiro
Uchino, Takashi
contents Moire superlattices (MSLs) are an emerging class of two-dimensional functional materials whose electronic states can be tuned by the twist angle between two van der Waals layers and/or the relative placement of the layers. The intriguing properties of MSLs are closely correlated to the moiré potential, which is the electrostatic potential induced by interlayer coupling. Intensive efforts have been made to understand the nature and distribution of the moire potential by using various experimental and theoretical techniques. However, the experimental observation of the moiré potential is still challenging because of the possible presence of the surface and/or interlayer contaminants. In this work, we develop a method to obtain hexagonal boron nitride (hBN) nanolayers (with or without twist) using a specially designed chemical exfoliation technique. The resulting hBN nanolayers are atomically clean and strain free, hence providing ideal MSLs for the investigation of their moiré potential. Aberration-corrected high resolution transmission electron microscopy measurements on the twisted hBN nanolayers allow us to observe moiré diffraction spots in Fourier space. Then, the moire potential is reconstructed by the inverse fast Fourier transform of the moire diffraction spots. It has been revealed that the local interlayer atomic overlap plays a decisive role in determining the periodicity and distribution of the moiré potential, as supported by density functional theory calculations. This work not only provides a general strategy to observe the moire potential in MSLs, but it also expands the application of electron microscopy to the further study of MSLs with atomic resolution.
format Preprint
id arxiv_https___arxiv_org_abs_2411_07653
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Atomic-Scale Observation of Moire potential in Twisted Hexagonal Boron Nitride Layers by Electron Microscopy
Mishima, Rina
Nagai, Takuro
Segawa, Hiroyo
Ehara, Masahiro
Uchino, Takashi
Materials Science
Mesoscale and Nanoscale Physics
Moire superlattices (MSLs) are an emerging class of two-dimensional functional materials whose electronic states can be tuned by the twist angle between two van der Waals layers and/or the relative placement of the layers. The intriguing properties of MSLs are closely correlated to the moiré potential, which is the electrostatic potential induced by interlayer coupling. Intensive efforts have been made to understand the nature and distribution of the moire potential by using various experimental and theoretical techniques. However, the experimental observation of the moiré potential is still challenging because of the possible presence of the surface and/or interlayer contaminants. In this work, we develop a method to obtain hexagonal boron nitride (hBN) nanolayers (with or without twist) using a specially designed chemical exfoliation technique. The resulting hBN nanolayers are atomically clean and strain free, hence providing ideal MSLs for the investigation of their moiré potential. Aberration-corrected high resolution transmission electron microscopy measurements on the twisted hBN nanolayers allow us to observe moiré diffraction spots in Fourier space. Then, the moire potential is reconstructed by the inverse fast Fourier transform of the moire diffraction spots. It has been revealed that the local interlayer atomic overlap plays a decisive role in determining the periodicity and distribution of the moiré potential, as supported by density functional theory calculations. This work not only provides a general strategy to observe the moire potential in MSLs, but it also expands the application of electron microscopy to the further study of MSLs with atomic resolution.
title Atomic-Scale Observation of Moire potential in Twisted Hexagonal Boron Nitride Layers by Electron Microscopy
topic Materials Science
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2411.07653