2010/06/30 by Rahul Nandkishore, Leonid Levitov
Materials Science · Physics and Astronomy · #Graphene research and applications #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.82.115431
published as Phys. Rev. B 82, 115431 (2010) · 12 pages, 3 figures
openalex publication_date 2010/09/17 · arxiv created 2010/09/20 · arxiv updated 2010/09/21 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We analyze the many-body properties of bilayer graphene (BLG) at charge neutrality, governed by long-range interactions between electrons. Perturbation theory in a large number of flavors is used in which the interactions are described within a random phase approximation, taking account of dynamical screening effect. Crucially, the dynamically screened interaction retains some long-range character, resulting in log2 renormalization of key quantities. We carry out the perturbative renormalization group calculations to one loop order and find that BLG behaves to leading order as a marginal Fermi liquid. Interactions produce a log squared renormalization of the quasiparticle residue and the interaction vertex function while all other quantities renormalize only logarithmically. We solve the RG flow equations for the Green's function with logarithmic accuracy and find that the quasiparticle residue flows to zero under RG. At the same time, the gauge-invariant quantities, such as the compressibility, remain finite to log2 order, with subleading logarithmic corrections. The key experimental signature of this marginal Fermi liquid behavior is a strong suppression of the tunneling density of states, which manifests itself as a zero bias anomaly in tunneling experiments in a regime where the compressibility is essentially unchanged from the noninteracting value.