The filling of the large van der Waals gap in Transition Metal Dichalcogenides (TMDs) often leads to lattice and electronic instabilities, which prelude the onset of a rich phenomenology. Motivated by previous results from macroscopic measurements, we investigate the electronic structure of the TMDs ${\mathrm{ZrTe}}_2$ and Ni intercalated ${\mathrm{ZrTe}}_2$ $({\mathrm{Ni}}_x{\mathrm{ZrTe}}_2,$ $x\approx 0.05)$ employing angle-resolved photoemission spectroscopy (ARPES). We readily identify in ${\mathrm{Ni}}_x{\mathrm{ZrTe}}_2$ two flat bands, most likely associated with localized Ni-derived $3d$-states, at about $\approx -0.7\mathrm{eV}$ and $\approx -1.2\mathrm{eV}$ in binding energy. More significantly, at low $T$, we identify an electronic structure reconstruction in ${\mathrm{Ni}}_x{\mathrm{ZrTe}}_2$, which halves the electronic periodicity along the $k_z$ direction. This is reminiscent of a commensurate band folding with wave vector $q=(0,0,\pi )$. A mean-field model for a charge density wave (CDW) transition driven by interband hole-hole interactions is solved with inputs from the experimentally determined electronic band structure. Comparison between theory and experiments unveils a CDW transition in ${\mathrm{Ni}}_x{\mathrm{ZrTe}}_2$, for which the gap opens above the Fermi level. Our findings invite further investigation into the structural properties of intercalated ${\mathrm{ZrTe}}_2$.

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• Electronic structure
• Dirac semimetal
• Transition metal dichalcogenides
• Angle-resolved photoemission spectroscopy