2018/12/31 by Niels B. M. Schröter, Ding Pei, Maia G. Vergniory +18 · 1 citation
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Band gap #Brillouin zone #Condensed matter physics #Electron #Electronic band structure #Fermi Gamma-ray Space Telescope #Fermi level #Fermi surface #Fermion #Geometry #Graphene research and applications #Homogeneous space #Physics #Quantum mechanics #Semimetal #Topological Materials and Phenomena #Topological insulator #Topology (electrical circuits) #Weyl semimetal #cond-mat.mes-hall
paper · pdf · doi:10.1038/s41567-019-0511-y
published as Nature Physics (2019) https://www.nature.com/articles/s41567-019-0511-y · Original journal submission date Aug 17th 2018, v2 is the accepted manuscript
openalex publication_date 2019/05/06 · arxiv created 2020/03/25 · arxiv updated 2020/03/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Topological semimetals in crystals with a chiral structure (which possess a handedness due to a lack of mirror and inversion symmetries) are expected to display numerous exotic physical phenomena, including fermionic excitations with large topological charge [1], long Fermi arc surface states [2,3], unusual magnetotransport [4] and lattice dynamics [5], as well as a quantized response to circularly polarized light [6]. To date, all experimentally confirmed topological semimetals exist in crystals that contain mirror operations, meaning that these properties do not appear. Here, we show that AlPt is a structurally chiral topological semimetal that hosts new fourfold and sixfold fermions, which can be viewed as a higher spin eneralization of Weyl fermions without equivalence in elementary particle physics. These multifold fermions are located at high symmetry points and have Chern numbers larger than those in Weyl semimetals, thus resulting in multiple Fermi arcs that span the full diagonal of the surface Brillouin zone. By imaging these long Fermi arcs, we experimentally determine the magnitude and sign of their Chern number, allowing us to relate their dispersion to the handedness of their host crystal.