Metallic spin glasses

Recent work on the zero-temperature phases and phase transitions of strongly random electronic systems is reviewed. The transition between the spin glass and quantum paramagnet is examined, for both metallic and insulating systems. Insight gained from the solution of infinite-range models leads to a quantum field theory for the transition between a metallic quantum paramagnetic and a metallic spin glass. The finite-temperature phase diagram is described and crossover functions are computed in mean-field theory. A study of fluctuations about mean field leads to the formulation of scaling hypotheses.