Symmetry of the Gap Function in High-$T_c$ Superconductors

Mihir Arjunwadkar; D. G. Kanhere; G. Baskaran; Rahul Basu

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arXiv · cond-mat/9502008

Symmetry of the Gap Function in High-$T_c$ Superconductors

Mihir Arjunwadkar·D. G. Kanhere·G. Baskaran·Rahul Basu

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Abstract

One of the most debated issues related to high-$T_c$ superconductivity is the symmetry of the Cooper pair or the gap function. In this report, we present numerical results regarding the gap function in strongly correlated electron systems using $t-J$ and Hubbard models in one and two dimensions. To this end, we use exact diagonalization to study the ground states of 8- and 16-site clusters consisting of single or coupled layers. We calculate a reduced two-particle density matrix in momentum space which is a measure of the gap function. We then analyze the eigenvectors of this density matrix, which display the possible Cooper pair symmetries. The eigenvector corresponding to the largest eigenvalue indicates a vanishing gap on the Fermi surface (which is in favour of odd-gap pairing) although $d_{x^2-y^2}$ symmetry is seen to be a very close contestant in many of the cases.

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Mihir Arjunwadkar, D. G. Kanhere, G. Baskaran, Rahul Basu. 1995-02-23. Symmetry of the Gap Function in High-$T_c$ Superconductors. https://arxiv.org/abs/cond-mat/9502008

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