Quantum phase transition and superconductivity in ferromagnetic heavy-fermion systems

Ferromagnetic Kondo lattice systems have been shown to display the phenomenon of Kondo destruction [1], raising the prospect of quantum criticality in ferromagnetic heavy fermion systems in parallel with their antiferromagnetic counterparts [2]. The issue becomes particularly pressing given the recent developments on UTe2. This system shows strong evidence for spin-triplet superconducting pairing and indications of quantum criticality in the normal state [3,4]. In this work, we study a periodic Anderson model with ferromagnetic RKKY interactions. We treat the model within the extended dynamical mean-field theory [5] and solve the self-consistency equations with the continuous-time quantum Monte Carlo method [6]. We present the results on the underlying quantum phase transition and the superconducting pairing correlations, showing that the system has a strong tendency to triplet pairing.

[1] S. J. Yamamoto and Q. Si, PNAS 107, 15704 (2010).
[2] A. Steppke et al., Science 339, 933 (2013).
[3] S. Ran et al., Science 365, 684 (2019).
[4] S. Ran et al., arXiv:1909.06932.
[5] J. H. Pixley, A. Cai and Q. Si, Phys. Rev. B 91, 125127 (2015).
[6] A. Cai and Q. Si, Phys. Rev. B 100, 014439 (2019).