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SO(5) Symmetry in t-J and Hubbard Models

W. Hanke·R. Eder·E. Arrigoni·A. Dorneich·S. Meixner·M. G. Zacher
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Abstract

Numerical and analytical results are reviewed, which support SO(5) symmetry as a concept unifying superconductivity and antiferromagnetism in the high-temperature superconductors. Exact cluster diagonalizations verify that the low-energy states of the two-dimensional t-J and Hubbard models, widely used microscopic models for the high-Tc cuprates, form SO(5) symmetry multiplets. Apart from a small standard deviation ~J/10, these multiplets become degenerate at a critical chemical potential (transition into doped system). As a consequence, the d-wave superconducting states away from half-filling are obtained from the higher spin states at half-filling through SO(5) rotations. Between one and two dimensions, using weak-coupling renormalization, a rather general ladder Hamiltonian including next-nearest-neighbor hopping can be shown to flow to an SO(5) symmetric point. Experimental tests and consequences such as the existence of a pi-Goldstone mode both in the insulator and superconductor and, in particular, the relationship between the photoemission spectra of the insulator and superconductor, are emphasized.

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W. Hanke, R. Eder, E. Arrigoni, A. Dorneich, S. Meixner, M. G. Zacher. 1998-07-01. SO(5) Symmetry in t-J and Hubbard Models. https://doi.org/10.1007/bfb0107642

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