Disorder-Driven Non-Fermi-Liquid Behavior in Kondo Alloys

Abstract

We demonstrate that a model of disordered Anderson lattices can account for many non-Fermi liquid features observed in a number of Kondo alloys. Due to the exponential nature of the Kondo temperature scale, even moderate disorder leads to a rather broad distribution of Kondo temperatures, inducing strong effective disorder seen by the conduction electrons. Spins with very small Kondo temperatures remain unquenched and dominate the low temperature properties. The model predicts logarithmic divergences in thermodynamic quantities at low temperatures. We also find a linear temperature dependence of the resistivity, a feature that remained a stumbling block in previous theoretical attempts. We argue that for realistic amounts of disorder, such marginal Fermi liquid behavior is a very robust feature of disordered Kondo alloys.