Weyl-Kondo semimetal: Topological quantum phase transition by a Zeeman coupling

Recently a Weyl-Kondo semimetal (WKSM) has been concurrently discovered in theoretical^1,2 and experimental^3,4 studies. In the solutions to the Anderson lattice model with a nonsymmorphic, noncentrosymmetric crystalline lattice, in the presence of spin-orbit coupling, the Kondo effect cooperates with the space-group symmetry to drive the Weyl nodes and pin them at the Fermi energy. Intriguingly, recent experiments have uncovered how the magnetic field quenches the WKSM.⁵ Here, we studied the Anderson lattice model with a broken time reversal symmetry, via a Zeeman coupling.⁶ Tuning the Zeeman coupling controls the position and number of Weyl nodes and leads to the eventual annihilation of the nodes before the Kondo energy scale vanishes. Our results provide a microscopic understanding of the high-field experiments on the WKSM.

¹H.-H. Lai, S. E. Grefe, S. Paschen, and Q. Si, PNAS 115, 93 2018
²S. E. Grefe, H.-H. Lai, S. Paschen, and Q. Si, PRB 101, 075138 2020
³S. Dzsaber et al., PRL 118, 246601 2017
⁴S. Dzsaber et al., arXiv:1811.02819 2018
⁵S. Dzsaber et al., arXiv:1906.01182 2019
⁶S. E. Grefe, H.-H. Lai, S. Paschen, and Q. Si, Weyl-Kondo semimetal: towards control of Weyl nodes, 2020