Laboratoire de Physique Théorique
Toulouse - UMR 5152

After a brief introduction to the topic of magnetic quantum criticality in metallic systems, I will present a study of the Kondo-Heisenberg model in three dimensions. The mean field phase diagram exhibits a spin liquid phase and a heavy-fermion phase, separated by a quantum critical point where an energy scale associated with Kondo hybridization vanishes. The quantum critical regime of this system has a small, but finite, temperature scale. Above this scale the critical fluctuations associated with the vanishing Kondo hybridization has a dynamical exponent , giving rise to a resistivity which has temperature dependence. The transport and thermodynamic properties near this quantum critical point will be discussed in light of recent experiments on heavy fermion systems.