Eliashberg theory of excitonic insulating transition in graphene

Abstract

A sufficiently strong Coulomb interaction may open an excitonic fermion gap and thus drive a semimetal-insulator transition in graphene. In this paper, we study the Eliashberg theory of excitonic transition by coupling the fermion gap equation self-consistently to the equation of vacuum polarization function. Including the fermion gap into polarization function increases the effective strength of Coulomb interaction because it reduces the screening effects due to the collective particle-hole excitations. Although this procedure does not change the critical point, it leads to a significant enhancement of the dynamical fermion gap in the excitonic insulating phase. The validity of the Eliashberg theory is justified by showing that the vertex corrections are suppressed at large $N$ limit.

8 pages, 6 figures

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Cited by in corpus (10)

• Excitonic pairing and insulating transition in two-dimensional semi-Dirac semimetals
• Field theoretic renormalization study of reduced quantum electrodynamics and applications to the ultra-relativistic limit of Dirac liquids
• Dynamical gap generation in graphene with frequency dependent renormalization effects
• Excitonic mass gap in uniaxially strained graphene
• The role of frequency dependence in dynamical gap generation in graphene
• Screening and gap generation in bilayer graphene
• Dynamical gap generation in 2D Dirac semimetal with deformed Dirac cone
• Coulomb center instability in bilayer graphene
• Robustness of the semimetal state of Na3Bi and Cd3As2 against Coulomb interaction
• Quantum critical phenomena of the excitonic insulating transition in two dimensions