Quantum criticality and global phase diagram of an Ising-anisotropic Kondo lattice

Abstract

Recent studies of heavy-fermion systems with tunable quantum fluctuations have focused on a variety of zero-temperature phase transitions that involve not only the onset of magnetic order but also the destruction of Kondo entanglement. Motivated by these developments, we investigate the effect of enhanced quantum fluctuations induced by a transverse magnetic field in an Ising-anisotropic Kondo lattice model, solved within an extended dynamical mean field theory using the numerical renormalization group. A line of locally critical points describes a direct transition from a Kondo-screened paramagnetic heavy-fermion state to a Kondo-destroyed antiferromagnetic phase. Along the line, the extracted critical exponents remain unchanged. By probing the the interplay between quantum fluctuations of the local moments, the Kondo effect, and magnetic order, this study provides significant new insight into the global phase diagram of heavy-fermion systems.