Accueil > Français > Événements > Séminaires > Séminaires Magnétisme et Supraconductivité > Archives 2009

Inhomogeneous superconductivity and normal state properties in low dimensional organic compounds and ropes of carbon nanotubes

S. Charfi-Kaddour - LPMC, Département de Physique, Faculté des Sciences de Tunis, Campus Universitaire 1060 Tunis, Tunisie


It has been reported that, in low dimensional organic conductors, superconductivity may coexist macroscopically with non-superconducting states giving rise to an inhomogeneous phase. We investigate, based on the time dependent Ginzburg-Landau theory, the effect of disorder on the stability of the superconducting phase in such mixed state. We show that the superconducting transition temperature in these compounds is reduced by disorder but does not obey to the Abrikosov-Gorkov law [1]. We discuss recent experimental results concerning the case of high Tc superconductors with a nanoscale disorder.
We also focus on the interplay between superconductivity and disorder in ropes of carbon nanotubes which are good candidates to study the effect of dimensionality on the superconducting order. We show that, contrary to what is expected, disorder may enhance superconductivity in ropes of carbon nanotubes [2].

 

The second part of the seminar will be devoted to the normal state properties of two dimensional organic conductors (-(BEDT-TTF)2X). Based on a Fermi liquid approach we probe the role of spin fluctuations on quasi-particles behaviour in the normal state. We have calculated the spectral function at different points of the Fermi surfaces. We found that, due to nesting properties, quasi-particle weights vanish at some points, which is reminiscent of NMR experiments. Our results may explain the anomalous properties of the normal state of -(BEDT-TTF)2X salts [3,4].

 

[1] S. Haddad et al. EPL 80, 17001 (2007)

[2] B. Bellafi et al. to appear in Physica B

[3] R. Louati, Phys. Rev. B 62, 5957 (2000)

[4] D. Meddeb, et al. to appear in Physica B

Affiche PDF