Schedule Oct 12, 2012
Overscreened Kondo Fixed Point in S=1 Spin Liquid
Maksym Serbyn (MIT)

Authors: Maksym Serbyn, T. Senthil, and Patrick A. Lee

Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139

We propose a possible realization of overscreened Kondo impurity problem by magnetic s=1/2 impurity embedded in a two-dimensional S=1 U(1) spin liquid with a Fermi surface. This problem contains interesting interplay between non Fermi liquid behavior induced by U(1) gauge field coupled to fermions and  non Fermi liquid fixed point in the overscreened Kondo problem. Using large-N expansion together with expansion in dynamical exponent of gauge field, we find that coupling to gauge field leads to weak but observable changes in physical properties of the system at the overscreened Kondo fixed point. We discuss extrapolation of our results to the physical case and argue that realization of the overscreened Kondo physics could lead to observation of effects due to gauge field. Physical systems that can possibly realize the effect are also discussed.

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