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Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
Published on: July 24, 2015
Energy gaps in graphene nanoribbons
Young-Woo Son1, Marvin L Cohen, Steven G Louie
1Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA.
Physical Review Letters
|December 13, 2006
Summary
We developed scaling rules for graphene nanoribbon (GNR) band gaps using first-principles calculations. Our findings reveal the crucial role of edge structure and quantum confinement in determining GNR band gaps.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Computational Physics
Background:
- Graphene nanoribbons (GNRs) exhibit tunable electronic properties.
- Understanding band gap formation in GNRs is crucial for electronic applications.
- Previous models like tight-binding and Dirac equation solutions have limitations.
Purpose of the Study:
- To establish scaling rules for GNR band gaps based on width.
- To elucidate the physical mechanisms behind band gap formation in different GNR edge types.
- To validate theoretical predictions with ab initio calculations.
Main Methods:
- First-principles calculations (ab initio methods).
- Analysis of armchair and zigzag edged GNRs with hydrogen passivation.
- Analytical modeling including edge effects.
Main Results:
- GNRs with both armchair and zigzag edges possess band gaps, contrary to some simpler models.
- Quantum confinement and edge effects dictate band gaps in armchair GNRs.
- Edge magnetization and staggered sublattice potential cause band gaps in zigzag GNRs.
Conclusions:
- Scaling rules for GNR band gaps are derived from first-principles.
- The study clarifies the distinct origins of band gaps in armchair and zigzag GNRs.
- Analytical models accurately reproduce ab initio results, highlighting the importance of edge physics.
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