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Excitons in insulating cuprates

M. E. Simón·A. A. Aligia·C. D. Batista·E. R. Gagliano·F. Lema
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Abstract

We study the electronic excitations near the charge-transfer gap in insulating CuO$_2$ planes, starting from a six-band model which includes $% p_π$ and $d_{xy}$ orbitals and Cu-O nearest-neighbor repulsion $U_{pd}$. While the low lying electronic excitations in the doped system are well described by a modified $t-J$ model, the excitonic states of the insulator include hybrid $d_{xy}-$ $p_π$ states of $A_{2g}$ symmetry. We also obtain excitons of symmetries $B_{1g}$ and $E_u$, and eventually $A_{1g}$, which can be explained within a one-band model. The results agree with observed optical absorption and Raman excitations.

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M. E. Simón, A. A. Aligia, C. D. Batista, E. R. Gagliano, F. Lema. 1996-01-22. Excitons in insulating cuprates. https://doi.org/10.1103/physrevb.54.r3780

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