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Absence of edge reconstruction for quantum Hall edge channels in graphene devices.

Authors :
Coissard A
Grushin AG
Repellin C
Veyrat L
Watanabe K
Taniguchi T
Gay F
Courtois H
Sellier H
Sacépé B
Source :
Science advances [Sci Adv] 2023 May 12; Vol. 9 (19), pp. eadf7220. Date of Electronic Publication: 2023 May 12.
Publication Year :
2023

Abstract

Quantum Hall (QH) edge channels propagating along the periphery of two-dimensional (2D) electron gases under perpendicular magnetic field are a major paradigm in physics. However, groundbreaking experiments that could use them in graphene are hampered by the conjecture that QH edge channels undergo a reconstruction with additional nontopological upstream modes. By performing scanning tunneling spectroscopy up to the edge of a graphene flake on hexagonal boron nitride, we show that QH edge channels are confined to a few magnetic lengths at the crystal edges. This implies that they are ideal 1D chiral channels defined by boundary conditions of vanishing electronic wave functions at the crystal edges, hence free of electrostatic reconstruction. We further evidence a uniform charge carrier density at the edges, incompatible with the existence of upstream modes. This work has profound implications for electron and heat transport experiments in graphene-based systems and other 2D crystalline materials.

Details

Language :
English
ISSN :
2375-2548
Volume :
9
Issue :
19
Database :
MEDLINE
Journal :
Science advances
Publication Type :
Academic Journal
Accession number :
37172096
Full Text :
https://doi.org/10.1126/sciadv.adf7220