Exchange reaction between Li and Na intercalated into TiS2

Single crystals of TiS₂(0001) were intercalated sequentially by Li and Na. The intercalation occurred across the Van der Waals planes, by deposition onto the basal plane of TiS₂. The investigation took place in UHV by soft X-ray photoelectron spectroscopy. Deposition of Na onto Li-intercalated TiS₂(0001) caused the Li to move further into the bulk of the substrate. However, deposition of Li onto Na-intercalated TiS₂(0001) forced Na to move out towards the surface by an exchange mechanism. These interactions between intercalated Li and Na into TiS₂(0001) and their subsequent behaviour have been explained by a correlation of thermodynamic (Gibbs free energy), kinetic (diffusion coefficient) and electrostatic effects.