Surface Science Investigations of Cu Intercalation in 1T TaSe(2) and TiSe(2) and Its Deintercalation by Adsorbed Br(2)

The intercalation of Cu adsorbed onto IT TaSe(2) and TiSe(2) (0001) van der Waals planes as well its deintercalation by adsorbed Br(2) is studied by synchrotron induced photoelectron spectroscopy and low energy electron diffraction. Cu intercalation into 1T TaSe(2) leads to a change in lattice distortion (charge density waves) as is evident from a transition of a commensurate root 13x root 13 to a 3x3 superstructure and changes in Ta 4f core line and valence band spectra. For 1T TiSe(2) intercalation follows closely the rigid band model. After adsorption of Br(2) at 100 K and annealing to room temperature a CuBr overlayer is detected on both samples. The substrate spectra indicate the deintercalation of near surface Cu. The experimental results suggest that the diffusion of Cu proceeds normal to the van der Waals plane. Ionics