Analysis of the antiferromagnetic phase transitions of the 2D Kondo lattice

Abstract

We study the antiferromagnetic quantum phase transition of a 2D Kondo-Heisenberg square lattice using the nonlinear sigma model. A renormalization group analysis of the competing Kondo-RKKY interaction is carried out to one-loop order in the μ 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 renormalization group results also allow us to propose a new phase diagram near the antiferromagnetic fixed point of this 2D Kondo lattice model. © 2009 The American Physical Society.