We have investigated the charge-spin-ordering transition in La1.5Sr0.5NiO4 by measurements of Raman and optical conductivity spectra. The checkerboard-type charge ordering below ∼400 K can be probed by activated phonon (A 1g and E.,) and two-magnon (B 1g) modes in the infrared and Raman spectra as well as by formation of pseudogaps in the optical conductivity spectra. Besides, another B2g Raman mode emerges below 150 K together with reduction of the optical gap, which can be attributed to another ordering process, i.e., the stripe formation.
|ジャーナル||Physical Review B - Condensed Matter and Materials Physics|
|出版ステータス||Published - 2003 1 1|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics