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arXiv · 0902.0535

Phase diagram and single-particle spectrum of CuO$_2$ layers within a variational cluster approach to the 3-band Hubbard model

E. Arrigoni·M. Aichhorn·M. Daghofer·W. Hanke
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Abstract

We carry out a detailed numerical study of the three-band Hubbard model in the underdoped region both in the hole- as well as in the electron-doped case by means of the variational cluster approach. Both the phase diagram and the low-energy single-particle spectrum are very similar to recent results for the single-band Hubbard model with next-nearest-neighbor hoppings. In particular, we obtain a mixed antiferromagnetic+superconducting phase at low doping with a first-order transition to a pure superconducting phase accompanied by phase separation. In the single-particle spectrum a clear Zhang-Rice singlet band with an incoherent and a coherent part can be seen, in which holes enter upon doping around $(π/2,π/2)$. The latter is very similar to the coherent quasi-particle band crossing the Fermi surface in the single-band model. Doped electrons go instead into the upper Hubbard band, first filling the regions of the Brillouin zone around $(π,0)$. This fact can be related to the enhanced robustness of the antiferromagnetic phase as a function of electron doping compared to hole doping.

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E. Arrigoni, M. Aichhorn, M. Daghofer, W. Hanke. 2009-02-03. Phase diagram and single-particle spectrum of CuO$_2$ layers within a variational cluster approach to the 3-band Hubbard model. https://doi.org/10.1088/1367-2630%2F11%2F5%2F055066

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