Tunable many-body interactions in semiconducting graphene: Giant excitonic effect and strong optical absorption

Abstract

Electronic and optical properties of graphene depend strongly on many-body interactions. Employing the highly accurate many-body perturbation approach based on Green's functions, we find a large renormalization over independent particle methods of the fundamental band gaps of semiconducting graphene structures with periodic defects. Additionally, their exciton binding energies are larger than 0.4 eV, suggesting significantly strengthened electron-electron and electron-hole interactions. Their absorption spectra show two strong peaks whose positions are sensitive to the defect fraction and distribution. The strong near-edge optical absorption and excellent tunability make these two-dimensional materials promising for optoelectronic applications.

The GW Compendium: A Practical Guide to Theoretical Photoemission Spectroscopy

“…Moreover, the imaginary part of the self-energy becomes non-zero only at the plasmon poles, which implies that QP lifetimes cannot properly be calculated with PPMs, see Equation (98) and section 6.3. However, PPMs are still used in large scale G 0 W 0 calculations (Deslippe et al, 2012), for example for solids (Jain et al, 2011; Reyes-Lillo et al, 2016), surfaces (Löser et al, 2012), 2D materials (Dvorak and Wu, 2015; Qiu et al, 2016; Drüppel et al, 2018), graphene nanoribbons (Wang et al, 2016; Talirz et al, 2017) or polymers (Hogan et al, 2013; Lüder et al, 2016).…”

“…Other passivated graphenes also open a band gap (Klintenberg et al, 2010; Wei and Jacob, 2013a). One can also apply strain, poke holes, or form other planar carbon allotropes by rearranging carbon bonds, many of which open an appreciable band gap (~1 eV) in graphene at the GW level (Appelhans et al, 2010a,b; Liang et al, 2012; Nisar et al, 2012; Dvorak and Wu, 2015).…”

“…Ab-initio GW /BSE calculations focused on semiconductors like Si, GaAs, and Li 2 O where GW /BSE produces optical absorption spectra and exciton binding energies in close agreement with experiment (Onida et al, 1995b; Albrecht et al, 1997, 1998a,b; Benedict et al, 1998a,b; Rohlfing and Louie, 1998, 2000; Benedict and Shirley, 1999). Similar to the proliferation of GW since its early successes, GW /BSE has been applied extensively to solids (Schleife et al, 2011, 2018; Rinke et al, 2012; Erhart et al, 2014), molecules (Körbel et al, 2014; Bruneval et al, 2015; Jacquemin et al, 2015), surfaces (Palummo et al, 2004), and two-dimensional materials (Komsa and Krasheninnikov, 2012; Ramasubramaniam, 2012; Hüser et al, 2013a; Qiu et al, 2013, 2016; Shi et al, 2013; Ugeda et al, 2014; Dvorak and Wu, 2015). As with Dyson's equation, equations with the Bethe-Salpeter form appear in different contexts in many-body theory.…”

The GW compendium: A practical guide to theoretical photoemission spectroscopy

“…Moreover, the imaginary part of the self-energy becomes non-zero only at the plasmon poles, which implies that QP lifetimes cannot properly be calculated with PPMs, see Equation ( 98) and Section VI.C. However, PPMs are still used in large scale G 0 W 0 calculations (Deslippe et al, 2012), for example for solids (Jain et al, 2011;Reyes-Lillo et al, 2016), surfaces (Löser et al, 2012), 2D materials (Drüppel et al, 2018;Dvorak and Wu, 2015;Qiu et al, 2016), graphene nano ribbons (Talirz et al, 2017;Wang et al, 2016) or polymers (Hogan et al, 2013;Lüder et al, 2016).…”

“…Other passivated graphenes also open a band gap (Klintenberg et al, 2010;Wei and Jacob, 2013a). One can also apply strain, poke holes, or form other planar carbon allotropes by rearranging carbon bonds, many of which open an appreciable band gap (∼ 1 eV) in graphene at the GW level (Appelhans et al, 2010a,b;Dvorak and Wu, 2015;Liang et al, 2012;Nisar et al, 2012).…”