Analysis of the Antiferromagnetic Phase Transitions of the 2D Kondo Lattice

We have studied the antiferromagnetic quantum phase transition of a 2D Kondo-Heisenberg square lattice using the non-linear sigma model. A renormalization group analysis of the competing Kondo – RKKY interaction was carried out to 1-loop order in the expansion, and a new quantum critical point (QCP) strongly affected by Kondo fluctuations is found. Near this QCP, the spin-wave velocity scales logarithmically, i.e. breakdown of hydrodynamic behavior, and the spin-wave is logarithmically frozen out. The RG results also allow us to propose a new phase diagram near the antiferromagnetic fixed point of this 2D Kondo lattice model.