Photoemission spectra of $\mathrm{S}{\mathrm{r}}_2\mathrm{Cu}{\mathrm{O}}_2\mathrm{C}{\mathrm{l}}_2$: a theoretical analysis

Abstract

Recent angle resolved photoemission (ARPES) results for the insulating cuprate $\mathrm{S}{\mathrm{r}}_2\mathrm{Cu}{\mathrm{O}}_2\mathrm{C}{\mathrm{l}}_2$ have provided the first experimental data which can be directly compared to the (theoretically) well--studied problem of a single hole propagating in an antiferromagnet. The ARPES results reported a small bandwidth, providing evidence for the existence of strong correlations in the cuprates. However, in the same experiment some discrepancies with the familiar 2D $\mathrm{t}-\mathrm{J}$ model were also observed. Here we discuss a comparison between the ARPES results and the quasiparticle dispersion of both (i) the $\mathrm{t}-{\mathrm{t}}^{\prime }-\mathrm{J}$ Hamiltonian and (ii) the three--band Hubbard model in the strong--coupling limit. Both model Hamiltonians show that the experimentally observed one--hole band structure can be approximately reproduced using reasonable values for ${\mathrm{t}}^{\prime }$, or the direct oxygen hopping amplitude ${\mathrm{t}}_{\mathrm{pp}}$.

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