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Superconducting states in frustrating t-J model: A model connecting high-$T_c$ cuprates, organic conductors and Na$_x$CoO$_2$

Masao Ogata
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Abstract

The two-dimensional t-J model on a frustrating lattice is studied using mean-field variational theories with Gutzwiller approximation. We find that a superconducting state with broken time-reversal symmetry (d+id state) is realized in the parameter region close to the triangular lattice. The frustration enlarges the region of superconductivity when $t<0$ for the hole-doped case, which is equivalent to $t>0$ for electron doping. We also discuss the SU(2) degeneracy at half-filling. The d+id state probably corresponds to the spin gap state at half-filling.

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Masao Ogata. 2003-04-17. Superconducting states in frustrating t-J model: A model connecting high-$T_c$ cuprates, organic conductors and Na$_x$CoO$_2$. https://doi.org/10.1143/jpsj.72.1839

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