Weyl-Kondo Semimetal -- How Strong Correlations Intersect with Electronic Topology*

Strong correlations in metals are known to yield a rich variety of quantum phases. Whether and how they also drive electronic topology is of considerable current interest and, yet, a largely open question. A promising setting arises in heavy fermion systems, which may feature not only strong correlations but also a large spin-orbit coupling. Recently, a Weyl-Kondo semimetal phase has been concurrently discovered in theoretical [1] and experimental [2] studies. The theoretical work was carried out in a Kondo lattice model that is time-reversal invariant but inversion-symmetry breaking. The non-symmorphic space-group symmetry and strong correlations cooperate to produce Weyl nodal excitations with highly reduced velocity as well as to pin the resulting Weyl nodes to the Fermi energy. In this talk, I will present these theoretical developments, describe in some detail the interplay between the Kondo interaction and space-group symmetry [3] and, motivated by recent high-field experiments on Ce3Bi4Pd3 [4], the control of the Weyl nodes [5]. I will also touch upon the results on other Kondo lattice models, which are constructed based on space-group symmetry constraints. Finally, I will discuss the enrichment of our results for the strong correlation physics, in the form of a global phase diagram, of heavy fermion metals [6].

References:

[1] H.-H. Lai et al, PNAS 115, 93 (2018)

[2] S. Dzsaber et al, Phys. Rev. Lett. 118, 246601 (2017); ibid, arXiv:1811.02819

[3] S. E. Grefe et al, Phys. Rev. B101, 075138 (2020)

[4] S. Dzsaber et al, arXiv:1906.01182

[5] S. E. Grefe et al, unpublished (2020); JPS Conf. Proc. 30, 011013 (2020)

[6] S. Paschen and Q. Si, Nat. Rev. Phys. (arXiv:2009.03602); Phys. Status Solidi B 250, 425 (2013)