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TT: Fachverband Tiefe Temperaturen
TT 65: Poster Session Topological Topics
TT 65.13: Poster
Donnerstag, 19. März 2020, 15:00–19:00, P2/EG
de Haas–van Alphen measurements of CoSi — •B.V. Schwarze1,2, J. Hornung1,2, K. Manna3, T. Förster1, and J. Wosnitza1,2 — 1Hochfeld-Magnetlabor Dresden (HLD-EMFL), HZDR, Dresden, Germany — 2Institut für Festkörper- und Materialphysik, TU Dresden, Germany — 3Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden, Germany
It is known from angle-resolved photoemission spectroscopy (ARPES) that CoSi hosts unconventional chiral fermions. It exhibits a topological threefold band-touching node with a Chern number of +2 at the Γ point and a topological fourfold band-touching node with a Chern number of -2 at the R point. These nodes are protected by crystal symmetries and connected by giant surface Fermi arcs. They generate spin-1 fermions and charge-2 double Weyl fermions, respectively. We performed de Haas-van Alphen (dHvA) measurements up to 18 T and down to 40 mK. The angular dependence of the fundamental dHvA frequencies as well as their effective masses are in good agreement with our density-functional-theory calculations, confirming the topologically non-trivial band structure. We also observed multiple magnetic-breakdown frequencies, providing further information on the topological phase shift.