Local probe of bulk and edge states in a fractional Chern insulator

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Main Authors: Ji, Zhurun, Park, Heonjoon, Barber, Mark E., Hu, Chaowei, Watanabe, Kenji, Taniguchi, Takashi, Chu, Jiun-Haw, Xu, Xiaodong, Shen, Zhi-xun
Format: Preprint
Published: 2024
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author Ji, Zhurun
Park, Heonjoon
Barber, Mark E.
Hu, Chaowei
Watanabe, Kenji
Taniguchi, Takashi
Chu, Jiun-Haw
Xu, Xiaodong
Shen, Zhi-xun
author_facet Ji, Zhurun
Park, Heonjoon
Barber, Mark E.
Hu, Chaowei
Watanabe, Kenji
Taniguchi, Takashi
Chu, Jiun-Haw
Xu, Xiaodong
Shen, Zhi-xun
contents Fractional quantum Hall effect (FQHE) is a prime example of topological quantum many-body phenomena, arising from the interplay between strong electron correlation, topological order, and time reversal symmetry breaking. Recently, a lattice analog of FQHE at zero magnetic field has been observed, confirming the existence of a zero-field fractional Chern insulator (FCI). Despite this, the bulk-edge correspondence -- a hallmark of FCI featuring an insulating bulk with conductive edges -- has not been directly observed. In fact, this correspondence has not been visualized in any system for fractional states due to experimental challenges. Here we report the imaging of FCI edge states in twisted MoTe2 by employing a newly developed modality of microwave-impedance microscopy. By tuning the carrier density, we observe the system evolving between metallic and FCI states, the latter of which exhibits insulating bulk and conductive edges as expected from bulk-boundary correspondence. We also observe the evolution of edge states across the topological phase transition from an incompressible Chern insulator state to a metal and finally to a putative charge ordered insulating state as a function of interlayer electric field. The local measurement further reveals tantalizing prospects of neighboring domains with different fractional orders. These findings pave the way for research into topologically protected 1D interfaces between various anyonic states at zero magnetic field, such as topological entanglement entropy, Halperin-Laughlin interfaces, and the creation of non-abelian anyons.
format Preprint
id arxiv_https___arxiv_org_abs_2404_07157
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Local probe of bulk and edge states in a fractional Chern insulator
Ji, Zhurun
Park, Heonjoon
Barber, Mark E.
Hu, Chaowei
Watanabe, Kenji
Taniguchi, Takashi
Chu, Jiun-Haw
Xu, Xiaodong
Shen, Zhi-xun
Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
Fractional quantum Hall effect (FQHE) is a prime example of topological quantum many-body phenomena, arising from the interplay between strong electron correlation, topological order, and time reversal symmetry breaking. Recently, a lattice analog of FQHE at zero magnetic field has been observed, confirming the existence of a zero-field fractional Chern insulator (FCI). Despite this, the bulk-edge correspondence -- a hallmark of FCI featuring an insulating bulk with conductive edges -- has not been directly observed. In fact, this correspondence has not been visualized in any system for fractional states due to experimental challenges. Here we report the imaging of FCI edge states in twisted MoTe2 by employing a newly developed modality of microwave-impedance microscopy. By tuning the carrier density, we observe the system evolving between metallic and FCI states, the latter of which exhibits insulating bulk and conductive edges as expected from bulk-boundary correspondence. We also observe the evolution of edge states across the topological phase transition from an incompressible Chern insulator state to a metal and finally to a putative charge ordered insulating state as a function of interlayer electric field. The local measurement further reveals tantalizing prospects of neighboring domains with different fractional orders. These findings pave the way for research into topologically protected 1D interfaces between various anyonic states at zero magnetic field, such as topological entanglement entropy, Halperin-Laughlin interfaces, and the creation of non-abelian anyons.
title Local probe of bulk and edge states in a fractional Chern insulator
topic Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2404.07157