Manifestation of incommensurate structural modulations in the Ti-L-2,L-3 electron energy-loss near-edge structure of Sr2TiSi2O8

作者：Hoeche T^*; Grodzicki M; Heyroth F; Uecker R; Van Aken P A

来源：Philosophical Magazine Letters, 2007, 87(6): 431-439.

DOI：10.1080/09500830701227536

Structural modulations hosted by complex oxides are - beyond relative orientation changes of 'rigid units' - accompanied by characteristic distortions of coordination polyhedra. Electronic structure calculations in the local density approximation, performed at model clusters derived from positionally modulated structures, proved that the molecular - orbital structure also sensitively reflects such distortions. The latter crystal-field splitting of unoccupied states is accessible by high-resolution electron energy-loss near-edge structure (ELNES) spectroscopy. However, since ELNES spectra average over many different individual target-ion environments, the resulting ELNES possesses significantly broadened spectral features. In this contribution, such broadening is shown to dramatically influence the spectral shape of the Ti-L-2,L-3 ELNES acquired at the strongly modulated fresnoite framework compound Sr2TiSi2O8.

• 出版日期2007
• 单位中国科学院金属研究所