Deformation of anisotropic Fermi surfaces due to electron-electron interactions

We study the effect of electron-electron interactions in the electronic properties of a biased graphene bilayer. This system is a semiconductor with conduction and valence bands characterized by an unusual "mexican-hat" dispersion. We focus on the metallic regime where the chemical potential lies in the "mexican-hat" in the conduction band, leading to a topologically non-trivial Fermi surface in the shape of a ring. We show that due to the unusual topology of the Fermi surface electron-electron interactions are greatly enhanced. We show that the ferromagnetic instability can occur provided a low density of carriers. We compute the electronic polarization function in the random phase approximation and show that, while at low energies the system behaves as a Fermi liquid (albeit with peculiar Friedel oscillations), at high frequencies it shows a highly anomalous response when compare to ordinary metals.

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“…[10]). The ImP ∼ |ǫ| −1/2 dependence found in this range translates into a quasiparticle lifetime which decays as Γ(ǫ) ∝ |ǫ − ǫ F | 25 .…”

Section: The Plasmon Spectrummentioning

confidence: 94%

Fermi liquid theory of a Fermi ring

et al. 2007

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“…The self-energy, within this approximation, can show a significant momentum dependence when the initial FS is anisotropic and lies near hot spots, where the quasiparticles are strongly scattered. 11 This simultaneous calculation of the FS and the second-order self-energy corrections is a fo rmidable task. However, the knowledge of the exact shape of the FS of a material is very important since it may affect the transport properties as well as the collective behavior, and have valuable information from the point of view of theory in order to find the appropriate model to study the system.…”

Section: Introductionmentioning

confidence: 99%

Self-energy corrections to anisotropic Fermi surfaces

et al. 2006

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The electron-electron interactions affect the low-energy excitations of an electronic system and induce deformations of the Fermi surface. These effects are especially important in anisotropic materials with strong correlations, such as copper-oxide superconductors or ruthenates. Here we analyze the deformations produced by electronic correlations in the Fermi surface of anisotropic two-dimensional systems, treating the regular and singular regions of the Fermi surface on the same footing. Simple analytical expressions are obtained for the corrections, based on local features of the Fermi surface. It is shown that, even for weak local interactions, the behavior of the self-energy is nontrivial, showing a momentum dependence and a self-consistent interplay with the Fermi surface topology. Results are compared to experimental observations and to other theoretical results.

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Effect of electron-electron interaction on the Fermi surface topology of doped graphene

2008

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The electron-electron interactions effects on the shape of the Fermi surface of doped graphene are investigated. The actual discrete nature of the lattice is fully taken into account. A π-band tightbinding model, with nearest-neighbor hopping integrals, is considered. We calculate the self-energy corrections at zero temperature. Long and short range Coulomb interactions are included. The exchange self-energy corrections for graphene preserve the trigonal warping of the Fermi surface topology, although rounding the triangular shape. The band velocity is renormalized to higher value. Corrections induced by a local Coulomb interaction, calculated by second order perturbation theory, do deform anisotropically the Fermi surface shape. Results are compared to experimental observations and to other theoretical results.

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Deformation of anisotropic Fermi surfaces due to electron-electron interactions

Cited by 3 publications

References 35 publications

Fermi liquid theory of a Fermi ring

Fermi liquid theory of a Fermi ring

Self-energy corrections to anisotropic Fermi surfaces

Effect of electron-electron interaction on the Fermi surface topology of doped graphene

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