Quantum Critical Strange Metal and Fermi Surface Reconstruction in a large-<i>N</i> Kondo Lattice Model

Quantum critical points in heavy Fermion materials, involving a change of the Fermi surface volume, have presented a long standing puzzle. One way to describe such a transition within a Kondo lattice model is through condensation of a slave Boson. However, this approach leads to a weakly coupled critical point, which fails to describe non-Fermi liquid behavior, such as the ubiquitously observed T-linear resistivity at criticality. We present a modified large-N Kondo lattice model, which also describes a transition from a small Fermi surface to a heavy Fermi liquid with a large Fermi surface, but gives rise to T-linear resistivity at the critical point. In the large-N limit we also compute the behavior of the Hall transport properties across the transition and compare the results to recent experiments with CeCoIn₅. We show under what conditions a strong enhancement of the Hall coefficient, seen in the experiment, is expected.