Impact of Electron-Hole Correlations on the 1T-TiSe2 Electronic Structure

Several experiments have been performed on 1T-TiSe2 in order to identify whether the electronic structure is semimetallic or semiconducting without reaching a consensus. In this paper, we theoretically study the impact of electron-hole and electron-phonon correlations on the bare semimetallic and semiconducting electronic structure. The resulting electron spectral functions provide a direct comparison of both cases and demonstrate that 1T-TiSe2 is of predominant semiconducting character with some spectral weight crossing the Fermi level.