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Antiferromagnetic to superconducting phase transition in the hole- and electron-doped Hubbard model at zero temperature

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

The competition between d-wave superconductivity (SC) and antiferromagnetism (AF) in the high-Tc cuprates is investigated by studying the hole- and electron-doped two-dimensional Hubbard model with a recently proposed variational quantum-cluster theory. The approach is shown to provide a thermodynamically consistent determination of the particle number, provided that an overall shift of the on-site energies is treated as a variational parameter. The consequences for the single-particle excitation spectra and for the phase diagram are explored. By comparing the single-particle spectra with quantum Monte-Carlo (QMC) and experimental data, we verify that the low-energy excitations in a strongly-correlated electronic system are described appropriately. The cluster calculations also reproduce the overall ground-state phase diagram of the high-temperature superconductors. In particular, they include salient features such as the enhanced robustness of the antiferromagnetic state as a function of electron doping and the tendency towards phase separation into a mixed antiferromagnetic-superconducting phase at low-doping and a pure superconducting phase at high (both hole and electron) doping.

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M. Aichhorn, E. Arrigoni, M. Potthoff, W. Hanke. 2006-06-06. Antiferromagnetic to superconducting phase transition in the hole- and electron-doped Hubbard model at zero temperature. https://doi.org/10.1103/physrevb.74.024508

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