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Repulsion-Sustained Supercurrent and Flux Quantization in Rings of Symmetric Hubbard Clusters

Agnese Callegari·Michele Cini·Enrico Perfetto·Gianluca Stefanucci
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Abstract

We test the response to a threading magnetic field of rings of 5-site $C_{4v}$-symmetric repulsive Hubbard clusters connected by weak intercell links; each 5-site unit has the topology of a CuO$_{4}$ cluster and a repulsive interaction is included on every site. In a numerical study of the three-unit ring with 8 particles, we take advantage of a novel exact-diagonalization technique which can be generally applied to many-fermion problems. For O-O hopping we find Superconducting Flux Quantization (SFQ), but for purely Cu-Cu links bound pair propagation is hindered by symmetry. The results agree with W=0 pairing theory.

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Agnese Callegari, Michele Cini, Enrico Perfetto, Gianluca Stefanucci. 2003-10-17. Repulsion-Sustained Supercurrent and Flux Quantization in Rings of Symmetric Hubbard Clusters. https://doi.org/10.1103/physrevb.68.153103

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