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Updated: May 15, 2026
11:42
Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
Published on: July 24, 2015
Hall conductance in graphene with point defects.
S İslamoğlu1, M Ö Oktel, O Gülseren
1Department of Physics, Bilkent University, 06800 Ankara, Turkey. selcen@fen.bilkent.edu.tr
Summary
Point defects in graphene significantly alter Hall conductance. Weakly coupled impurities cause plateau disappearance, while strongly coupled impurities create new plateaus, impacting quantum Hall effects.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Mechanics
Background:
- Graphene exhibits quantum Hall effects, sensitive to lattice structure and defects.
- The Kubo formalism enables Hall conductance calculations without Fermi energy gap constraints.
Purpose of the Study:
- Investigate Hall conductance in graphene with point defects.
- Analyze the impact of impurity coupling and lattice symmetry on quantum Hall phenomena.
Main Methods:
- Utilized the Kubo formalism for Hall conductance calculations.
- Modeled graphene with a tight-binding Hamiltonian, including next-nearest neighbor hopping.
- Considered dilute, regular arrays of point defects.
Main Results:
- Pure graphene shows usual and anomalous integer quantum Hall effects near Dirac points.
- Weakly coupled impurities, especially vacancies, drastically modify Hall conductance near E=0 eV due to localized impurity states.
- Strongly coupled impurities form impurity bands, creating new Hall conductance plateaus at spectral extrema without significantly altering original spectrum values.
Conclusions:
- Point defect characteristics (coupling strength, localization) critically determine Hall conductance behavior in graphene.
- Graphene's quantum Hall effects are robust but can be tuned by controlled introduction of specific types of point defects.
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