Kondo destruction in multipolar order: Implications for heavy-fermion quantum criticality*

Motivated by the quantum-critical heavy-fermion systems [1,2] exhibiting multipolar orders, we theoretically study an effective field theory of a Kondo lattice model involving both spin and quadrupole degrees of freedom. The field theory contains a quantum non-linear sigma model of the antiferroquadrupolar (AFQ) phase in spin-1 systems, with Kondo couplings to conduction electrons. In the absence of the Kondo coupling, we demonstrate the stability of the AFQ phase using density matrix renormalization group analysis in the underlying spin model. We proceed to analyze the effect of the Kondo couplings, using a mixed fermion-boson renormalization group procedure [3]. We show that the Kondo couplings are exactly marginal, which implies a Kondo destruction in the multipolar phase. Our results provide theoretical basis for the recently advanced notion of sequential Kondo-destruction [1]. Implications of our results for the global phase diagram of the heavy fermion systems are discussed. [1] V. Martelli et al., arXiv:1709.09376. [2] J. Custers et al, Nat. Mater. 11, 189 (2012). [3] S. J. Yamamoto and Q. Si, Phys. Rev. B 81, 205106 (2010).