Synthesis and spectroscopic characterization of alkali-metal intercalated ZrSe₂

We report on the synthesis and spectroscopic characterization of alkali metal intercalated ZrSe₂ single crystals. ZrSe₂ is produced by chemical vapour transport and then Li is intercalated. Intercalation is performed from the liquid phase (via butyllithium) and from the vapour phase. Raman spectroscopy of intercalated ZrSe₂ reveals phonon energy shifts of the Raman active A_1g and E_g phonon modes, the disappearance of two-phonon modes and new low wavenumber Raman modes. Angle-resolved photoemission spectroscopy is used to perform a mapping of the Fermi surface revealing an electron concentration of 4.7 × 10¹⁴ cm^-2. We also perform vapour phase intercalation of K and Cs into ZrSe₂ and observe similar changes in the Raman modes as for the Li case.