Quasi-particle behaviour in normal state of kappa-(ET)2X compounds

Based on a Fermi liquid approach, using the random phase approximation, we studied the effect of spin fluctuations on the properties of the normal state of kappa-(BEDT-TTF)2X where the Fermi surface is assumed to depend basically on two parameters namely the bandwidth and the departure from perfect nesting. To probe the role of spin fluctuations on the behaviour of the quasi-particles 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. Our results, which are consistent with NMR experiments, may explain the anomalous properties of the normal state of kappa-(BEDT-TTF)2X salts.