1998/07/01 by W. Hanke, R. Eder, E. Arrigoni +3 · 1 citation
Materials Science · Physics and Astronomy · #Antiferromagnetism #Degenerate energy levels #Hamiltonian (control theory) #Hubbard model #Iron-based superconductors research #Organic and Molecular Conductors Research #Physics of Superconductivity and Magnetism #Spectral line #Superconductivity #Symmetry (geometry) #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1007/bfb0107642
published in Advances in solid state physics, 533-550 (Springer Science+Business Media) · LaTeX, 12 pages, 9 postscript figures. To appear in: Festkoerperprobleme/Advances in Solid State Physics
arxiv created 1998/07/01 · openalex publication_date 1999/01/01 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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.