Crossover from non-Fermi liquid to Fermi liquid behavior in heavy fermion systems

摘要

Many heavy fermion systems display a crossover from Fermi liquid to non-Fermi liquid behavior due to a nearby quantum critical point (QCP). Some of the features are universal and do not depend on the nature of the QCP and the tuning mechanism. A simple one-band model of heavy electrons is considered to describe the crossover. The nesting of the spherical Fermi surfaces of an electron and a hole pocket separated by a nesting vector Q and the interaction between electrons gives rise to itinerant antiferromagnetism. The order can be gradually suppressed by mismatching the nesting and a QCP is obtained as T_N tends to zero. We review our results on the specific heat, the quasi-particle linewidth, the electrical resistivity, the amplitudes of de Haas-van Alphen oscillations and the dynamical spin susceptibility.