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Momentum-Dependent Charge Transfer Excitations in Sr2CuO2Cl2 - Angle Resolved Electron Energy Loss Spectroscopy

Y. Y. Wang·F. C. Zhang·V. P. Dravid·K. K. Ng·M. V. Klein·S. E. Schnatterly·L. L. Miller
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Abstract

Electron-hole pair excitations in the insulating cuprates $Sr_2CuO_2Cl_2$ were investigated by angle-resolved electron energy loss spectroscopy. The optically allowed and optically forbidden transitions were observed to be strongly anisotropic in $Cu-O_2$ plane. The former show a large energy dispersion $\sim 1.5$eV along [110], and the latter appear at a higher energy position ($\sim 4.5$eV) 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.

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Y. Y. Wang, F. C. Zhang, V. P. Dravid, K. K. Ng, M. V. Klein, S. E. Schnatterly, L. L. Miller. 1996-06-10. Momentum-Dependent Charge Transfer Excitations in Sr2CuO2Cl2 - Angle Resolved Electron Energy Loss Spectroscopy. https://doi.org/10.1103/physrevlett.77.1809

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