Angle-resolved photoemission spectroscopy is employed to study the electronic structure of bulk ${\mathrm{TiSe}}_2$ before and after doping with potassium impurities. A splitting in the conduction band into two branches is observed after room-temperature deposition. The splitting energy increases to approximately 130 meV when the sample is cooled to 40 K. One branch exhibits a nondispersive two-dimensional feature, while the other shows the characteristics of three-dimensional bulk band dispersion. Core-level spectroscopy suggests that the K impurities predominantly occupy the intercalated sites within the van der Waals gap. The results indicate the formation of a quasi-freestanding ${\mathrm{TiSe}}_2$ layer. Additionally, doping completely suppresses the periodic lattice distortion in the surface region. These findings are further supported by density functional theory calculations, which compare the band structure of monolayer and bulk ${\mathrm{TiSe}}_2$ with experimental data. Thus, the dimensional and intrinsic electronic properties of $1T\text{−}{\mathrm{TiSe}}_2$ can be controlled through the intercalation procedure used in this work.

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• Charge density waves
• Excitons
• Jahn-Teller effect
• Peierls transition
• Transition metal dichalcogenides
• Angle-resolved photoemission spectroscopy
• Density functional theory
• Photoemission spectroscopy