Abstract:
The effect of Coulomb correlations on the electronic structure of bulk van der Waals material V$_2$Te$_2$O is studied by the charge self-consistent density functional theory and dynamical mean-field theory method. Our results show a significant correlation-induced renormalization of the spectral functions in the vicinity of the Fermi energy which is not accompanied by a transfer of the spectral weight to Hubbard bands. The computed quasiparticle effective mass enhancement $m^*/m$ for the V $3d$ states varies from $1.31$ to $3.32$ indicating an orbital-dependent nature of correlation effects and suggests an orbital-selective formation of local moments in the V $3d$ shell. We demonstrate that taking into account of Coulomb interaction between the V $3d$ electrons yields the electronic specific heat coefficient $\gamma = 26.94$ mJ K$^{-2}$ mol$^{-1}$ in reasonable agreement with the experiment. We show that the strength of Coulomb correlations is sufficient to trigger a band shift along the $Z-\Gamma-X$ path of the Brillouin zone leading to a collapse of the electronic Fermi surface pocket centered on the $\Gamma-Z$ direction predicted by density functional theory.
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