High spatial resolution charge sensing of quantum Hall states

• 成果类型: Article
• 署名作者: Li Chiu, Cheng-; Wang, Taige; Fan, Ruihua; Watanabe, Kenji; Taniguchi, Takashi; Liu, Xiaomeng; Zaletel, Michael P.; Yazdani, Ali
• 署名单位: Princeton University; Princeton University; University of California System; University of California Berkeley; United States Department of Energy (DOE); Lawrence Berkeley National Laboratory; National Institute for Materials Science; National Institute for Materials Science; Cornell University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-12732
• DOI: 10.1073/pnas.2424781122
• 发表日期: 2025-02-25
• 关键词: composite fermions; force microscopy; electron; transitions; cascade

摘要

Charge distribution offers a unique fingerprint of important properties of electronic systems, including dielectric response, charge ordering, and charge fractionalization. We develop an architecture for charge sensing in two- dimensional electronic systems in a strong magnetic field. We probe local change of the chemical potential in a proximitized detector layer using scanning tunneling microscopy, allowing us to infer the chemical potential and the charge profile in the sample. Our technique has both high energy (<0.3 meV) and spatial (<10 nm) resolution exceeding that of previous studies by an order of magnitude. We apply our technique to study the chemical potential of quantum Hall liquids in monolayer graphene under high magnetic fields and their responses to charge impurities. The chemical potential measurement provides a local probe of the thermodynamic gap of quantum Hall ferromagnets and fractional quantum Hall states. The screening charge profile reveals spatially oscillatory response of the quantum Hall liquids to charge impurities and is consistent with the composite Fermi liquid picture close to the half- filling. Our technique also paves the way to map moir & eacute; potentials, probe Wigner crystals, and investigate fractional charges in quantum Hall and Chern insulators.