investigated using torque magnetometry and density functional theory*

We have studied the fermiology of the type-II Dirac semimetal candidates (Ni, Zr) Te₂ using torque magnetometry. The measurements were carried out under applied fields up to 35 T and temperatures as low as 0.32 K. Results showed clear de Haas-van Alphen (dHvA) oscillations with one major frequency for ZrTe₂ at F ~ 530 T and three major frequencies for NiTe₂ at F₁ ~ 72 T, F₂ ~ 425 T, and F₃ ~ 630 T. Berry phase analyses suggested that NiTe₂ is a topologically nontrivial system whereas ZrTe₂ is a topologically trivial system. Additional analyses using the Lifshitz-Kosevich formula to determine the effective mass of the electron of both NiTe₂ and ZrTe₂ were also carried out. Electronic band structures were investigated using density functional theory (DFT) to support our experimental data.

Work at the West Texas A&M University is supported by the Killgore Faculty Research program, the KRC Faculty, Undergraduate, and Graduate Student Research Grants, and the Welch Foundation (Grant No. AE-0025); L.H. acknowledges the Department of Science and Technology (DST), India [Grant No. SR/WOS-A/PM-33/2018 (G)]; work at the National High Magnetic Field Laboratory was supported by NSF/DMR-1644779 and the State of Florida; B.K.P. and D.P. were supported by NSF/DMR-1707785.