Fermi surface of the chiral topological semimetal PtGa.

PtGa is a topological semimetal with giant spin-split Fermi arcs. Here, we report on angular-dependent de Haas-van Alphen (dHvA) measurements combined with band-structure calculations to elucidate the details of the bulk Fermi surface of PtGa. The strong spin-orbit coupling leads to eight bands crossing the Fermi energy that form a multitude of Fermi surfaces with closed extremal orbits and results in very rich dHvA spectra. The large number of experimentally observed dHvA frequencies make the assignment to the equally large number of calculated dHvA orbits challenging. Nevertheless, we find consistency between experiment and calculations verifying the topological character with maximal Chern number of the spin-split Fermi surface.