Abstract

In this presentation, we will report our recent progress on studying the topological properties of the correlated semimetals YbPtBi and RX (R = Ce, Pr, Sm; X=Sb, Bi). 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, as well as the ARPES measurements and DFT calculations [1]. Upon lowering temperature, the Kondo interaction between the 4f electrons and conduction electrons is strengthened and therefore the electronic bands are renormalized. As a result, the contributions of chiral anomaly to the magnetotransport become negligible in the heavy fermion state. Instead, we obtained evidence for Weyl fermions at low temperatures from the measurements of specific heat and topological Hall effect. [1]. These results demonstrate that the Weyl fermion state is modified upon increasing the hybridization strength, providing a good opportunity to study the relationship between topologic states, electron-electron correlations and quantum criticality. The RX family of materials show very large magnetoresistance. Both trivial and non-trivial band topologies are observed in these compounds [2]. Angular dependent magnetoresistance measurements and band structure calculations provide evidence for Weyl fermions in the field-induced ferromagnetic state of CeSb [3]. In PrSb a trivial topology is revealed [4], whereas evidence for a non-trivial topology is found in SmSb, which quantum oscillations show anomalous behavior [5].

[1] C. Y. Guo et al., arXiv: 1710.05522， Nat. Commun. (accepted). [2] P. Li et al., Phys. Rev. B 98 , 085103 (2018); X. Duan et al., arXiv: 1802.04554 [3] C. Y. Guo et. al., npj Quantum Materials 2, 39 (2017). [4] F. Wu et al., Phys. Rev. B 96 , 125122 (2018). [5] F. Wu et al., arXiv: 1807.03070 (2018).