Thickness dependent quantum oscillations in ferromagnetic Weyl metal SrRuO₃

In a Weyl semimetal, a unique Weyl-orbit quantum oscillations can appear resulting from a nonlocal cyclotron orbit that connects the top and bottom Fermi-arc surface states via the bulk Weyl nodes. In this talk, such a Weyl-orbit effect (WOE) will be demonstrated in untwinned thin films of ferromagnetic Weyl metal SrRuO3 (SRO). From thickness dependent measurements of the quantum oscillations with field strength up to 35 T, we uncovered an unusual small Fermi pocket with a light effective mass and an oscillation frequency of about 30 T, which behaves as a 2D-like Fermi-pocket and shows a maximum oscillation amplitude for film thickness in a range of 10 – 20 nm. In addition, unusual thickness dependent phase shift and also concave downward curvature in the Landau fan diagram were observed, which agrees well with the simulated curves based on WOE theory with nonadiabatic correction terms. Discussions between the simulations and experimental data will be provided to address the issue regarding the optimum film thickness for achieving dominant WOE contribution in Weyl metal SRO.