1202.0443 (J. Gonzalez)

Electron self-energy effects on chiral symmetry breaking in graphene    [PDF]

J. Gonzalez

We investigate the dynamical breakdown of the chiral symmetry in the theory
of Dirac fermions in graphene with long-range Coulomb interaction. We analyze
the electron-hole vertex relevant for the dynamical gap generation in the
ladder approximation, showing that it blows up at a critical value \alpha_c in
the graphene fine structure constant which is quite sensitive to many-body
corrections. Under static RPA screening of the interaction potential, we find
that taking into account electron self-energy corrections to the vertex
increases the critical coupling to \alpha_c \approx 4.9, for a number N = 4 of
two-component Dirac fermions. When dynamical screening of the interaction is
instead considered, the effect of Fermi velocity renormalization in the
electron and hole states leads to the value \alpha_c \approx 1.75 for N = 4,
substantially larger than that obtained without electron self-energy
corrections (\approx 0.99), but still below the nominal value of the
interaction coupling in isolated free-standing graphene.

View original: http://arxiv.org/abs/1202.0443