Interplay of Weyl-Kondo physics and quantum criticality in the Kondo semimetal CeRu₄Sn₆

Correlation-driven gapless topological phases are a vastly unexplored field of great current interest. In a joint effort of experiment [1,2] and theory [3], the Weyl-Kondo semimetal state in the heavy fermion material Ce₃Bi₄Pd₃ was recently established as a prime example. To advance the field and understand the stabilization mechanisms of such phases, it is crucial to identify other candidate materials. One strategy – coined by tentative evidence for quantum criticality found in Ce₃Bi₄Pd₃ [1] – is to search for novel topological phases in the vicinity of quantum critical points. The noncentrosymmetric Kondo semimetal CeRu₄Sn₆ was theoretically proposed to host type I and type II Weyl-nodes [4] and shows quantum critical behavior without any form of parameter tuning [5]. This makes it a unique platform to investigate the role of quantum critical fluctuations in the formation mechanism of Weyl-Kondo semimetals and is therefore the focus of our experimental investigations. We present magnetotransport and specific heat measurements on CeRu₄Sn₆ under hydrostatic pressure and discuss signatures of Weyl-Kondo physics and how they evolve in the p-B-T phase diagram. Intriguingly, a dome of Weyl-Kondo semimetal phase appears to nucleate out of the ambient pressure and zero field quantum critical regime [6].

[1] S. Dzsaber et al., Phys. Rev. Lett., 118, 246601 (2017)

[2] S. Dzsaber et al., Proc. Natl. Acad. Sci. U.S.A. 118, e2013386118 (2021)

[3] H.-H. Lai et al., Proc. Natl. Acad. Sci. U.S.A. 115, 93 (2018)

[4] Y. Xu et al., Phys. Rev. X 7, 011027 (2017)

[5] W. T. Fuhrman et al., Sci. Adv. 7, eabf9134 (2021)

[6] D. M. Kirschbaum et al., in preparation (2023)