2017/09/22 by V. Apinyan, T. K. Kopeć
Materials Science · Physics and Astronomy · #Band gap #Bilayer graphene #Condensed matter physics #Coulomb #Electron #Exciton #Graphene #Graphene research and applications #Pairing #Physics #Quantum and electron transport phenomena #Quantum mechanics #Superconductivity #Topological Materials and Phenomena #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.1016/j.physe.2017.09.015
published as Physica E 95 (2018) 108 · 17 pages, 22 figures
openalex publication_date 2017/09/22 · arxiv created 2017/12/13 · arxiv updated 2017/12/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
In this paper, we consider the spectral properties of the bilayer graphene with the local excitonic pairing interaction between the electrons and holes. We consider the generalized Hubbard model, which includes both intralayer and interlayer Coulomb interaction parameters. The solution of the excitonic gap parameter is used to calculate the electronic band structure, single-particle spectral functions, the hybridization gap, and the excitonic coherence length in the bilayer graphene. We show that the local interlayer Coulomb interaction is responsible for the semimetal-semiconductor transition in the double layer system, and we calculate the hybridization gap in the band structure above the critical interaction value. The formation of the excitonic band gap is reported as the threshold process and the momentum distribution functions have been calculated numerically. We show that in the weak coupling limit the system is governed by the Bardeen-Cooper-Schrieffer (BCS)-like pairing state. Contrary, in the strong coupling limit the excitonic condensate states appear in the semiconducting phase, by forming the Dirac's pockets in the reciprocal space.