Quasiparticle energies and excitonic effects of the two-dimensional carbon allotrope graphdiyne: Theory and experiment

Abstract

We report the electronic structure and optical properties of the recently synthesized stable two-dimensional carbon allotrope-graphdiyne based on first-principles calculations and experimental optical spectrum. Due to the enhanced Coulomb interaction in reduced dimensionality, the band gap of graphdiyne increases to 1.10 eV within the GW many-body theory from a 0.44 eV within the density functional theory. The optical absorption is dominated by excitonic effects with remarkable electron-hole binding energy of over 0.55 eV within the GW-Bethe Salpeter equation calculation. Experimental optical absorption of graphdiyne films is performed and comparison with the theoretical calculations is analyzed in detail.

Communication: Generalization of Koopmans’ theorem to optical transitions in the Hubbard model of graphene nanodots

“…[12][13][14][15] Exciton binding energies in quasi-one-dimensional graphene nanoribbons 16,17 and excitonic absorption in triangular graphene quantum dots with zigzag edges 18,19 have been studied by solving the Bethe-Salpeter from first principles or diagonalizing the configuration interaction Hamiltonian. In this work, we will show that the quasiparticle correction to the optical gap and exciton binding energy in graphene nanodots are dominated by the long-range Coulomb interaction and thus both become small when only on-site Hubbard interactions are present in the case of metal substrates.…”

Adsorption and growth of palladium clusters on graphdiyne

“…This value is intermediate between band gaps calculated using DFT with other exchange-correlation functionals (gaps in the range 0.4-0.5 eV) 33,42,43 and the value of 1.18 eV calculated by the hybrid B3LYP method 43 . A recent calculation within the many-body GW method predicts a gap of 1.10 eV 18 . The value of the gap is lowered to 0.79 eV in GDYPd, and width of the gap also continues as the anchored Pd n cluster grows in size.…”

Symmetry-dependent transport properties and bipolar spin filtering in zigzagα-graphyne nanoribbons

“…Besides graphene, graphyne, a new allotrope of carbon containing sp and sp 2 hybridized carbon atoms, has also been the subject of interest [20][21][22][23][24][25][26][27][28][29][30] . Due to the presence of acetylenic bonds in the structure, graphyne is thought to have rich electronic and optical properties that are different from those of graphene 31 .…”