We present ab initio many-body calculations of the optical absorption in bulk graphite, graphene and bilayer of graphene. Electron-hole interaction is included solving the Bethe-Salpeter equation on top of a GW quasiparticle electronic structure. For all three systems, we observe strong excitonic effects at high energy, well beyond the continuum of π→ π* transitions. In graphite, these affect the onset of σ→ σ* transitions. In graphene, we predict an excitonic resonance at 8.3 eV arising from a background continuum of dipole forbidden transitions. In the graphene bilayer, the resonance is shifted to 9.6 eV. Our results for graphite are in good agreement with experiments. © 2010 The American Physical Society.
Ab initio high-energy excitonic effects in graphite and graphene
Trevisanutto P. E.;
2010-01-01
Abstract
We present ab initio many-body calculations of the optical absorption in bulk graphite, graphene and bilayer of graphene. Electron-hole interaction is included solving the Bethe-Salpeter equation on top of a GW quasiparticle electronic structure. For all three systems, we observe strong excitonic effects at high energy, well beyond the continuum of π→ π* transitions. In graphite, these affect the onset of σ→ σ* transitions. In graphene, we predict an excitonic resonance at 8.3 eV arising from a background continuum of dipole forbidden transitions. In the graphene bilayer, the resonance is shifted to 9.6 eV. Our results for graphite are in good agreement with experiments. © 2010 The American Physical Society.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
