Unconventional Sequence of Fractional Quantum Hall States in Suspended Graphene.

Saved in:
Bibliographic Details
Title: Unconventional Sequence of Fractional Quantum Hall States in Suspended Graphene.
Authors: Feldman, Benjamin E., Krauss, Benjamin, Smet, Jurgen H., Yacoby, Amir
Source: Science (pre-March 2025). 9/7/2012, Vol. 337 Issue 6099, p1196-1199. 4p.
Subjects: Graphene, Compressibility, Quantum Hall effect, Many-body problem, Physics -- Methodology, Single electron transistors, Band gaps
Abstract: Graphene provides a rich platform to study many-body effects, owing to its massless chiral charge carriers and the fourfold degeneracy arising from their spin and valley degrees of freedom. We use a scanning single-electron transistor to measure the local electronic compressibility of suspended graphene, and we observed an unusual pattern of incompressible fractional quantum Hall states that follows the standard composite fermion sequence between filling factors v = 0 and 1 but involves only even-numerator fractions between v = 1 and 2. We further investigated this surprising hierarchy by extracting the corresponding energy gaps as a function of the magnetic field. The sequence and relative strengths of the fractional quantum Hall states provide insight into the interplay between electronic correlations and the inherent symmetries of graphene. [ABSTRACT FROM AUTHOR]
Copyright of Science (pre-March 2025) is the property of American Association for the Advancement of Science and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Psychology and Behavioral Sciences Collection
Description
Abstract:Graphene provides a rich platform to study many-body effects, owing to its massless chiral charge carriers and the fourfold degeneracy arising from their spin and valley degrees of freedom. We use a scanning single-electron transistor to measure the local electronic compressibility of suspended graphene, and we observed an unusual pattern of incompressible fractional quantum Hall states that follows the standard composite fermion sequence between filling factors v = 0 and 1 but involves only even-numerator fractions between v = 1 and 2. We further investigated this surprising hierarchy by extracting the corresponding energy gaps as a function of the magnetic field. The sequence and relative strengths of the fractional quantum Hall states provide insight into the interplay between electronic correlations and the inherent symmetries of graphene. [ABSTRACT FROM AUTHOR]
ISSN:00368075
DOI:10.1126/science.1224784