Coulomb Interactions and Renormalization of Anisotropic Flat 2D Bands
ORAL
Abstract
We discuss electron-electron Coulomb interaction effects in a system of highly anisotropic 2D higher-order “Dirac” fermions with electronic dispersion characterized by arbitrary (even) power in one direction, and linear in the other direction. This model contains the simple semi-Dirac case (power two) and describes flat unidirectional bands for higher powers.
We find that at low energy there is a very strong, double logarithmic renormalization of the dispersion in the flat direction, which can be treated by renormalization group techniques. This results in an extraordinary renormalization of the electronic spectrum, with restored quasi-linear behavior in momentum in both directions at low energies (up to log corrections).
Thus we conclude that Coulomb interactions tend to restore the band dispersion and the interpretation of experimental data at low temperatures has to take into account the strong Coulomb interaction effects which for flat anisotropic Dirac bands are much more pronounced compared to linear Dirac semimetals (such as graphene).
We find that at low energy there is a very strong, double logarithmic renormalization of the dispersion in the flat direction, which can be treated by renormalization group techniques. This results in an extraordinary renormalization of the electronic spectrum, with restored quasi-linear behavior in momentum in both directions at low energies (up to log corrections).
Thus we conclude that Coulomb interactions tend to restore the band dispersion and the interpretation of experimental data at low temperatures has to take into account the strong Coulomb interaction effects which for flat anisotropic Dirac bands are much more pronounced compared to linear Dirac semimetals (such as graphene).
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Presenters
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Valeri N Kotov
University of Vermont
Authors
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Valeri N Kotov
University of Vermont