Many-Electron Multiplet Theory Applied to O-Atom Vacancies in High-k Dielectrics

作者：Lucovsky Gerald^*; Miotti Leonardo; Bastos Karen Paz

来源：Japanese Journal of Applied Physics, 2011, 50(4): 04DA15.

DOI：10.1143/JJAP.50.04DA15

Two-electron multiplet theory has been used to develop a high-spin effective d(2) model for O-vacancy spin-allowed and spin-forbidden dipole transitions, and for negative ion state traps. The transition and negative ion states have been detected by X-ray absorption spectroscopy in the O K pre-edge regime of transition metal (TM) elemental oxides and complex oxides. Occupied ground and excited states of the model satisfy Hund's rules by (i) including only high-spin state arrangements and (ii) using many electron state term symbols consistent with Russell-Saunders coupling. Qualitative and quantitative agreement between theory and experiment is demonstrated by using Tanabe-Sugano energy level diagrams for (i) identifying the symmetries and spin states, and (ii) determining the relative energies of intra-d-state transitions that are allowed in the presence of an intermediate strength ligand field. This includes removal of the spin degeneracy for the allowed transitions by a cooperative Jahn-Teller effect. The effective d(2) model is applied to nanocrystalline thin films of ZrO2, HfO2, TiO2, and Lu2O3 and to illustrate the agreement between the new d(2) model and the X-ray absorption spectroscopy data. The new model has also been applied with the same degree of success to complex TM oxides and SiO2.

• 出版日期2011-4