Evidence for topological Kondo semimetals*

In this presentation, we will report our recent progress studying the topological properties of the correlated semimetals RX (R = Ce, Pr, Sm; X=Sb, Bi) and YbPtBi.
The RX family of materials display a very large magnetoresistance and non-trivial band topologies. Angular dependent magnetoresistance measurements and band structure calculations provide evidence for Weyl fermions in the field-induced ferromagnetic state of CeSb [1]. In PrSb a trivial topology is revealed [2], whereas a non-trivial topology is found in SmSb, where quantum oscillations show anomalous behavior. Meanwhile in RBi, band inversions and topological surface states are revealed by ARPES measurements.
Evidence for Weyl fermions has also been found in the heavy fermion semimetal YbPtBi. At higher temperatures where the Kondo interaction is weaker, the presence of Weyl fermions is inferred from the chiral anomaly in magnetotransport measurements [3]. However, when the electronic bands become heavy at low temperatures due to the Kondo interaction, thermodynamic evidence for Weyl fermions emerges in the specific heat, as predicted theoretically [4]. These results show clear evidence for the influence of strong electronic correlations on the Weyl fermion state, opening up the opportunity for studying the interplay between Weyl fermions, electron-electron correlations and quantum criticality.
[1] C. Y. Guo et. al., npj Quantum Materials 2, 39 (2017).
[2] F. Wu et al., Phys. Rev. B 96, 125122 (2017).
[3] C. Y. Guo et al., arXiv: 1710.05522.
[4] H. –H. Lai et al., arXiv:1612.03899.