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Electron-electron and spin-orbit interactions in armchair graphene ribbons
1Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio 45701-2979, USA.
Physical Review Letters
|February 1, 2008
Summary
Intrinsic spin-orbit interactions create spin-filtered edge states in graphene ribbons, unlike insulating graphene planes. Coulomb interactions open a charge-gap, which shrinks with ribbon width.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Nanotechnology
Background:
- Graphene ribbons exhibit unique electronic properties influenced by their finite width.
- Understanding the interplay of spin-orbit and Coulomb interactions is crucial for predicting graphene's low-energy behavior.
Purpose of the Study:
- To investigate the impact of intrinsic spin-orbit and Coulomb interactions on the low-energy properties of finite-width graphene armchair ribbons.
- To analyze the emergence of metallic states and charge-gaps in these structures.
Main Methods:
- Utilized a Dirac Hamiltonian model to simulate the electronic behavior.
- Analyzed the effects of intrinsic spin-orbit interactions and Coulomb interactions separately and in combination.
Main Results:
- Intrinsic spin-orbit interactions lead to metallic states as spin-filtered edge states, contrasting with insulating graphene planes.
- Coulomb interactions induce a charge-gap in neutral ribbons, inversely proportional to ribbon width (Δ ≈ 1/W).
- Weak intrinsic spin-orbit interactions do not alter the insulating nature, and the spin sector remains gapless.
Conclusions:
- Finite-width graphene ribbons display distinct electronic properties compared to bulk graphene due to confinement and interactions.
- The study provides explicit expressions for width-dependent gaps and correlation functions, valuable for theoretical and experimental research.
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