Quantum Criticality in Kondo Lattice Model: A Renormalization Group Study Via Quantum non-Linear Sigma Model

When quasiparticles in a metal interact by exchanging soft collective modes, their dynamics tend to develop singularities which, if sufficiently strong, may even destroy the quasiparticle-coherence. The possibility of such quasiparticleless metallic states has long motivated theoretical and experimental investigations into itinerant systems at the edge of quantum phase transitions. Since heavy-fermion metals naturally possess the two necessary components, itinerant electrons and fluctuating local moments, they have played a key role in shaping our understanding of quantum critical metals [1]. Here, we study the antiferromagnet- to-paramagnet transition of a Kondo lattice model. We assess the effect of Kondo coupling through a renormalization group analysis. Our results shed new light on the global phase diagram of the heavy fermion systems [2] and, especially, the behavior of frustrated Kondo lattice[3,4].

[1] S. Paschen & Q. Si, Nat. Rev. Phys. 3, 9-26 (2021); S. Kirchner et al, RMP. 92, 011002 (2020); Q. Si et al., Nature 413, 804 (2001)

[2] Q. Si, Physica B378, 23 (2006); Phys. Status Solidi B 247, 476 (2010).

[3] H. Zhao et al, Nat. Phys. 15, 1261 (2019).

[4] M. Kavai et al, Nat. Comm. 12, 1377 (2021).