  The WHM - type materials (W=Zr/Hf/La, H=Si/Ge/Sn/Sb, M=O/S/Se/Te) have been
predicted to be a large pool of topological materials. These materials allow
for fine tuning of spin-orbit coupling, lattice constant and structural
dimensionality for various combinations of W, H and M elements, thus providing
an excellent platform to study how these parameters' tuning affect topological
semimetal state. In this work, we report the high field quantum oscillation
studies on ZrGeM (M=S, Se, and Te). We have found the first experimental
evidence for their theoretically-predicted topological semimetal states. From
the angular dependence of quantum oscillation frequency, we have also studied
the Fermi surface topologies of these materials. Moreover, we have compared
Dirac electron behavior between the ZrGeM and ZrSiM systems, which reveals deep
insights to the tuning of Dirac state by spin-orbit coupling and lattice
constants in the WHM systems.
