Antiferromagnetism and superconductivity in layered organic conductors: Variational cluster approach.
The kappa-(ET)2X layered conductors (where ET stands for BEDT-TTF) are studied within the dimer model as a function of the diagonal hopping t' and Hubbard repulsion U. Antiferromagnetism and d-wave superconductivity are investigated at zero temperature using variational cluster perturbation theory (VCPT). For large U, Néel antiferromagnetism exists for t' < t(c2)', with t(c2)' approximately 0.9. For fixed t', as U is decreased (or pressure increased), a d(x2-y2) superconducting phase appears. When U is decreased further, then a d(xy) order takes over. There is a critical value of t(c1)' approximately 0.8 of t' beyond which the AF and dSC phases are separated by the Mott disordered phase.
Sahebsara
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Département de physique and Regroupement québécois sur les matériaux de pointe, Université de Sherbrooke, Sherbrooke, Québec, Canada, J1K 2R1.
Sénéchal
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