Abstract
The insertion of lithium in anatase nanoparticles under ultrahigh vacuum (UHV) conditions is studied using x-ray absorption spectroscopy (XAS) and resonant photoelectron spectroscopy (RPES) at the Ti edge. It is demonstrated that XAS can be used to monitor the separation into an anatase phase and a lithium titanate phase of formal stoichiometry . The initial state properties of the Ti states of the lithium titanate phase are investigated using ab initio electronic structure calculations. The calculations show a correlation driven separation of Ti states from the conduction band in agreement with previous studies. It is shown that Ti in different oxidation states ( and ) is formed as a direct consequence of the electron-electron interaction. RPES and XAS spectra confirm the presence of electronically inequivalent Ti sites. The site-sensitivity of the RPES spectra at selected electron binding energies is found to be consistent with the calculations.
- Received 15 October 2004
DOI:https://doi.org/10.1103/PhysRevB.71.235419
©2005 American Physical Society