Interaction between Li and Na intercalated into 1T-TaSe2 layer compounds

In this work we study the adsorption of Li on a Na-intercalated TaSe2(0001) and, reversibly, the deposition of Na on a Li-intercalated TaSe2(0001) sur face. The intercalation occurred by deposition of the alkali elements onto the basal plane of the TaSe2. The experiment was performed in UHV by soft X ray photoelectron spectroscopy, using synchrotron radiation as excitation s ource. Lithium intercalation into 1T-TaSe2 leads to a phase transition of t he substrate from 1T to 2H polytypism. Lithium and sodium appear to compete in the intercalation process. Sodium pushes the preintercalated Li deeper into the bulk of the substrate, whereas, in the case of Li on Na-intercalat ed TaSe2, an exchange reaction takes place and part of the Na deintercalate s.