Electronic and topological properties of Ce-based honeycomb ferromagnet Ce 2 Zn 6 Ge 3

Ce 2 Zn 6 Ge 3 is a rare example of the Ce-based honeycomb ferromagnet. Here, we report its Fermi surface and topological properties by quantum oscillations via the magnetoresistance and tunnel diode oscillator (TDO) based measurements, in combination with the density functional theory (DFT) calculations. Four fundamental frequencies are observed in the quantum oscillations, and their angle dependence is more compatible with the DFT calculations assuming that the 4 f-electrons are localized, suggesting a localized nature of ferromagnetism in Ce 2 Zn 6 Ge 3. Furthermore, the observations of negative longitudinal magnetoresistance and non-zero Berry phase, as well as the existence of two pairs of Weyl points near the Fermi level as revealed from the calculated electronic structures, provide strong evidence for nontrivial topology in Ce 2 Zn 6 Ge 3. These findings suggest that Ce 2 Zn 6 Ge 3 could provide a unique platform to study magnetism, topology, quantum criticality and their interplay.