2016/05/20 by B. S. Monozon, Boris Monozon, Peter Schmelcher · 6 citations
Materials Science · Physics and Astronomy · #2D Materials and Applications #Adiabatic process #Condensed matter physics #Exciton #Graphene #Graphene nanoribbons #Graphene research and applications #Hamiltonian (control theory) #Molecular physics #Physics #Quantum and electron transport phenomena #Quantum mechanics #Rydberg formula #cond-mat.mes-hall
paper · pdf · doi:10.1016/j.physb.2016.07.009
published in Physica B Condensed Matter 500, 89-97 (Elsevier BV)
arxiv created 2016/05/20 · openalex publication_date 2016/07/12 · arxiv updated 2016/08/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We develop an analytical approach to the exciton optical absorption for narrow gap armchair graphene nanoribbons (AGNR). We focus on the regime of dominant size quantization in combination with the attractive electron-hole interaction. An adiabatic separation of slow and fast motions leads via the two-body Dirac equation to the isolated and coupled subband approximations. Discrete and continuous exciton states are in general coupled and form quasi Rydberg series of purely discrete and resonance type character. Corresponding oscillator strengths and widths are derived. We show that the exciton peaks are blue-shifted, become broader and increase in magnitude upon narrowing the ribbon. At the edge of a subband the singularity related to the 1D density of states is transformed into finite absorption via the presence of the exciton. Our analytical results are in good agreement with those obtained by other methods including numerical approaches. Estimates of the expected experimental values are provided for realistic AGNRs.