Abstract
Electron-hole pair excitations in the insulating cuprates Sr2CuO2Cl2 were investigated by angle-resolved electron energy loss spectroscopy. The optically allowed and optically forbidden transitions were observed to be strongly anisotropic in Cu - O2 plane. The former show a large energy dispersion 1.5eV along [110], and the latter appear at a higher energy position (4.5eV) only along [100], but not along [110]. We interpret these results as transitions involving excitons. A small exciton model is examined to explain both the observed features.
Original language | English (US) |
---|---|
Pages (from-to) | 1809-1812 |
Number of pages | 4 |
Journal | Physical review letters |
Volume | 77 |
Issue number | 9 |
DOIs | |
State | Published - 1996 |
ASJC Scopus subject areas
- Physics and Astronomy(all)