engleski

Spectral properties of Dirac liquid

We present the extension of our previous G0W0 approach to the two-dimensional system of massless Dirac electrons interacting via the long-range Coulomb interaction. We determine the one-particle spectral function taking into account only a partially filled band above the Dirac point. The electron self-energy is calculated paying particular attention to the contribution coming from the collective plasmon mode. The obtained results show a wide structure in the spectral function with the pronaunced weight just below the Dirac point and the absence of low energy quasi-particle. Dirac fermions have been applied in condensed matter physics to study variety of novel materials, including graphene and recently discovered three-dimensional topologycal insulators. Both systems have been investigated by angle resolved photoelectron spectroscopy (ARPES) measurements that provide direct probe of the electronic structure and the electron self-energy which takes into account electronic correlations and comprises collective modes. Our earlier G0W0 approach to spectral properties of quasi-one-dimensional conductors introduced wide features into the spectral function originating from the anisotropic plasmon dispersion due to finite electron-electron Coulomb interaction. Also, the early G0W0 approach to the three-dimensional , , jellium'' model resulted in the spectral function showing the low energy quasi-particle peaks and the additional features due to the plasmon mode. Analog results were reported for graphene.

Dirac liquid; spectral function; plasmon mode

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