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Published on: July 24, 2015
Ab initio GW many-body effects in graphene
Paolo E Trevisanutto1, Christine Giorgetti, Lucia Reining
1Institut Néel, CNRS and UJF, Grenoble, France.
Physical Review Letters
|December 31, 2008
Summary
This study uses many-body GW calculations to accurately model freestanding graphene's electronic band structure. Results show a 17% increase in Fermi velocity and a kink near the Dirac point, matching experimental findings.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Computational Physics
Background:
- Graphene exhibits unique electronic properties near its Dirac point.
- Accurate theoretical modeling is crucial for understanding these properties.
- Previous methods like density-functional theory have limitations.
Purpose of the Study:
- To perform an ab initio many-body GW calculation of graphene's band structure.
- To incorporate electron-electron interactions and correlation effects.
- To compare theoretical results with experimental observations.
Main Methods:
- Ab initio numerical many-body GW calculation.
- Inclusion of full ionic and electronic structure.
- Self-energy calculations with non-Hermitian and dynamical terms.
Main Results:
- Fermi velocity renormalization shows a 17% increase compared to DFT LDA, aligning better with experiments.
- A kink in the linear dispersion near the Dirac point is observed.
- The kink is attributed to low-energy pi-->pi* excitations and pi plasmons.
Conclusions:
- The GW self-energy improves the description of graphene's electronic band structure.
- The calculated Fermi velocity and kink phenomenon agree well with experimental data.
- The GW approximation does not predict a band gap opening in freestanding graphene.
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