Strong correlations in a magnetic chiral topological semimetal close to a correlated metal-insulator transition

Chiral topological semimetals are a new class of quantum materials that host multifold fermions with large topological charges and long Fermi-arc surface states. We have recently identified a family of non-magnetic intermetallic compounds crystallizing in the cubic B20 as chiral topological semimetals and visualized their multifold fermions and long fermi-arcs with angle-resolved photoemission (ARPES) [1,2]. In this talk, I will present our latest ARPES study of a magnetic chiral topological semimetal. The spectral function of the majority spin-channel is strongly broadened and almost completely smeared out in the vicinity of the Gamma point where a multifold fermion has been predicted by ab-initio calculations, whilst the minority spin channel shows long-lived quasiparticles up to 500 meV binding energy. Such spin-dependent electronic correlations have previously been observed in elemental ferromagnets, but to the best of my knowledge, such a drastic loss of quasiparticle weight has never been observed in a topological metal and may indicate a correlated topological metal-insulator transition.

[1] N. B. M. Schröter et al., Nat. Phys. 15, 759–765 (2019).

[2] N. B. M. Schröter et al., Science 369, 179 (2020).