Sequential Kondo destruction in an SU(4) Bose-Fermi Kondo model

Quantum criticality and the beyond-Landau physics of Kondo destruction [1,2] in heavy fermion systems with multipolar degrees of freedom is attracting considerable interest. Recent experiment on the heavy fermion compound Ce3Pd20Si6 shows evidence of two consecutive Fermi surface collapsing quantum phase transitions (QPT) as a function of magnetic field [3]. We advance a theory of two stages of Kondo effect. We consider an SU(4) Bose-Fermi Kondo model with both spin and orbital degrees of freedom, which represents an effective model for a multipolar Kondo lattice system. As a function of coupling strength to the bosonic baths, we find that a generic trajectory in the parameter space contains two QPTs, each being associated with the Kondo destruction of spin or orbital degrees of freedom. For Kondo lattice, this corresponds to two stages of Fermi surface jump, thus providing a natural understanding of the experimental findings.

[1] Q. Si et al., Nature 413, 804 (2001)
[2] S. Paschen et al., Nature 432, 881 (2004)
[3] V. Martelli et al., arXiv:1709.09376].