Spectral properties of Dirac electron system

We present the extension of our previous G0W0G0W0 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 linear band above the Dirac point. The electron self-energy is calculated, paying particular attention to the contribution coming from the collective plasmon mode through the dynamically screened Coulomb electron–electron interaction. The obtained results show a dispersing feature in the spectral function and a low energy quasi-particle with the renormalized spectral weight. We expect the results obtained to be qualitatively in agreement with spectral properties of monolayer of MoS2 which has the large direct band gap between the valence and conduction bands. We also discuss the influence of the underlying substrate on the obtained results.