Weyl Kondo semimetals in the quantum critical and magnetic regimes

The interplay between topology and strong electronic correlations has emerged as a key theme in quantum materials. The Weyl–Kondo semimetal illustrates how correlations, together with crystalline symmetry, can generate and stabilize Weyl nodes near the Fermi energy [1–3]. A compelling open question is whether such topological states can persist when the Fermi-liquid framework itself breaks down. Along this direction, we have substantiated the existence of non–Fermi-liquid topological phases in two distinct settings: (i) multichannel Kondo quantum-critical phase [4] and (ii) Weyl–Kondo semimetals near metallic quantum criticality [5]. In both cases, we show that symmetry constraints imposed on the electronic Green’s function enable the emergence of non–Fermi-liquid topological semimetal states. In parallel, we have shown how crystalline symmetry can be harnessed to preserve the quantum fluctuations of the Kondo effect even inside antiferromagnetic order, thereby realizing the counterintuitive magnetic Weyl–Kondo semimetal phase [6]. Finally, by introducing the concept of compact molecular orbitals, we identified new classes of topological semimetals that arise from strong correlations in bulk flat bands [7]. Together, these results provide a versatile  framework for understanding and identifying correlated topological semimetals in strongly interacting systems.

 

References:

 

[1] L. Chen et al, Topological semimetals driven by strong correlations and crystalline symmetry, Nat. Phys. 18, 1341 (2022)

[2] H.-H. Lai, S. E. Grefe, S. Paschen, and Q. Si, PNAS 115, 93 (2018)

[3] S. Dzsaber et al., PNAS 118, e2013386118 (2021); Phys. Rev. Lett. 118, 246601 (2017)

[4] H. Hu, L. Chen et al., Topological semimetals without quasiparticles, to be published (2025)

[5] D. M. Kirschbaum, L. Chen et al., Emergent topological semimetals, arXiv:2404.15924 (2024)

[6] Y. Fang, L. Chen, et al., Magnetic Weyl-Kondo semimetals induced by quantum fluctuations, arXiv:2403.02295

[7] L. Chen et al., Emergent flat band and topological Kondo semimetal driven by orbital-selective correlations, Nat. Comm. 15, 5242 (2024).