Dynamical response functions and collective modes of bilayer graphene

Physical Review B - Condensed Matter and Materials Physics

Volumn 80, Issue 24, 2009, Pages

  Borghi, Giovanni ^a   Polini, Marco ^b   Asgari, Reza ^c   MacDonald, A H ^d  

^a SISSA   (Italy)

^b CNR   (Italy)

^c INSTITUTE FOR STUDIES IN THEORETICAL PHYSICS AND MATHEMATICS IPM   (Iran)

^d UNIVERSITY OF TEXAS AT AUSTIN   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 77954716667     PISSN: 10980121     EISSN: 1550235X     Source Type: Journal    
DOI: 10.1103/PhysRevB.80.241402     Document Type: Article

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18. RPA is of course not exact. It should be viewed as a good starting point to analyze the collective behavior of charged many-particle systems. Its use in graphene away from the neutrality point is partly justified. For perturbative treatments of interactions in bilayer graphene it is the fine-structure constant α ee, rather than the density as in a normal 2D electron gas, which acts as a small parameter. The value of this parameter, which just depends on the dielectric environment surrounding BLG, is quite small (∼ 0.5) for samples deposited on SiO 2 or grown on SiC.
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24. The mixed sum and difference response functions vanish because the system Hamiltonian is invariant under spatial inversion.
25. The model's particle-hole symmetry guarantees that electron-doped and hole-doped bilayers have identical properties.
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