Weyl-Kondo semimetal: controlling the nodes via magnetic field*

In the effort to study topological metals in strongly-correlated settings, a Weyl-Kondo semimetal (WKSM) has been concurrently discovered in theoretical¹ and experimental^2,3 studies. This time-reversal-invariant state appears in a non-centrosymmetric Kondo lattice model. The theoretical and experimental signatures of the WKSM phase, include correlations-enhanced specific heat C=Γ T³ and a giant topological Hall response from the Kondo-driven Weyl nodes being pinned near the Fermi energy. Recently, high magnetic field experiments revealed a two-stage quantum phase transition, including a topological transition from the WKSM to a Kondo insulator.⁴ To connect with these experiments, we studied an Anderson lattice model with terms that break both time reversal and inversion symmetries.⁵ Tuning these terms controls the position and number of Weyl nodes in the Brillouin zone, and several topologically distinct phases emerge in this model.

¹H.-H. Lai, S. E. Grefe, S. Paschen, and Q. Si, PNAS 115, 93 2018
²S. Dzsaber et al., PRL 118, 246601 2017
³S. Dzsaber et al., arXiv:1811.02819 2018
⁴S. Dzsaber et al., arXiv:1906.01182 2019
⁵S. E. Grefe, H.-H. Lai, S. Paschen, and Q. Si, Weyl-Kondo semimetal: towards control of Weyl nodes 2019