Angle-resolved photoemission spectroscopy combined with band structure calculations have shown that the layered transition metal dichalcogenide ${\mathrm{NiTe}}_2$ is a type-II Dirac semimetal. However, conflicting conclusions were reported regarding the role of electron correlations in ${\mathrm{NiTe}}_2$. We study core levels and valence band electronic structure of single-crystal ${\mathrm{NiTe}}_2$ using soft and hard x-ray photoemission spectroscopy, x-ray absorption spectroscopy (XAS), and Ni $2p-3d$ resonant photoemission spectroscopy to quantify electronic parameters in ${\mathrm{NiTe}}_2$. The Ni $3d$ on-site Coulomb energy ($U_{dd}$) is quantified from measurements of the Ni $3d$ single-particle density of states and the two-hole correlation satellite. The Ni $2p$ core level and $L$-edge XAS spectra are analyzed by charge-transfer (CT) cluster model calculations using the experimental $U_{dd}$, and it shows that ${\mathrm{NiTe}}_2$ exhibits a negative CT energy $\mathrm{\Delta }$. A comparative analysis of NiO $L$-edge XAS confirms its well-known strongly correlated CT insulator character, with a larger $U_{dd}$ and positive $\mathrm{\Delta }$. The $d\text{−}p$ hybridization strength $T_{eg}$ for ${\mathrm{NiTe}}_2<\mathrm{NiO}$ shows that $T_{eg}$ is not responsible for reducing $U_{dd}$ in ${\mathrm{NiTe}}_2$ compared to NiO. The negative $\mathrm{\Delta }$ and a reduced $U_{dd}$ lead to the increase in the $d^n$ count on the Ni site in ${\mathrm{NiTe}}_2$ by nearly one electron. However, importantly, since $U_{dd}>\left|\mathrm{\Delta }\right|$, a finite repulsive $U_{dd}$ results in pushing $d$ states away from Fermi level and this is required to make ${\mathrm{NiTe}}_2$ a moderately correlated Dirac semimetal with band inversion in the $p\text{−}p$-type lowest-energy excitations.

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• Electronic structure
• Topological materials
• Transition metal dichalcogenides
• Photoemission spectroscopy
• X-ray absorption spectroscopy