SKM 2021 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 25: Poster Session: Topology

TT 25.4: Poster

Thursday, September 30, 2021, 13:30–16:00, P

Observation of symmetry-enforced topological nodal planes in CoSi — Nico Huber¹, •Kirill Alpin², Grace L. Causer¹, Lukas Worch¹, Andreas Bauer¹, Georg Benka¹, Moritz M. Hirschmann², Andreas P. Schnyder², Christian Pfleiderer^1,3,4, and Marc A. Wilde¹ — ¹Physik Department, Technische Universität München, Garching, Germany — ²Max-Planck-Institute for Solid State Research, Stuttgart, Germany — ³MCQST, Technische Universität München, Garching, Germany — ⁴Centre for Quantum Engineering (ZQE), Technische Universität München, Garching, Germany

In this work, we present a complete topological classification of CoSi, whose bandstructure features a plethora of Weyl points, topologically charged multifold crossings, and symmetry-enforced nodal planes. The latter are forced to have nonzero charges in the presence of SOC, which we show both theoretically for a general case and computationally via DFT calculations for CoSi, using an adaptive mesh of Wilson loops. The total charge is found to be consistent with the fermion doubling theorem. Resulting topological protectorates, intersections of the Fermi surface with topological nodal planes, are detected via measurements of Shubnikov-de Haas oscillations.