The dimer model for κ-phase organic superconductors
Dipartimento di Chimica Generale ed Inorganica, Chimica Analitica
e Chimica Fisica Università di Parma - I-43100 Parma, Italy
2 Istituto di Chimica Quantistica ed Energetica Molecolare Consiglio Nazionale delle Ricerche - I-56126 Pisa, Italy
Accepted: 30 March 1998
We prove that the upper electronic bands of κ-phase BEDT-TTF salts are adequately modeled by a tight-binding lattice with one site per cell. The band parameters are derived from recent ab initio calculations, getting a very simple but extremely accurate one-electron picture. This picture allows us to solve the BCS gap equation adopting a real-space pairing potential. Comparison of the resulting superconducting properties with experiments points to isotropic s0-pairing. Residual many-body or phonon-mediated interactions offer a plausible explanation of the large variety of physical properties observed in κ-phase BEDT-TTF salts.
PACS: 74.70.Kn – Organic superconductors / 74.20.Fg – BCS theory and its development / 74.25.Jb – Electronic structure
© EDP Sciences, 1998