Quantum oscillations with angular dependence in PdTe2single crystals.

ABSTRACT

The layered transition-metal dichalcogenide PdTe2has been discovered to possess bulk Dirac points as well as topological surface states. By measuring the magnetization (up to 7 T) and magnetic torque (up to 35 T) in single crystalline PdTe2, we observe distinct de Haas-van Alphen (dHvA) oscillations. Eight frequencies are identified withH||c, with two low frequencies (Fα= 8 T andFß= 117 T) dominating the spectrum. The effective masses obtained by fitting the Lifshitz-Kosevich (LK) equation to the data aremα*=0.059m0andmß*=0.067m0wherem0is the free electron mass. The corresponding Landau fan diagrams allow the determination of the Berry phase for these oscillations resulting in values of ∼0.67πfor the 3D α band (hole-type) (down to the 1st Landau level) and ∼0.23π-0.73πfor the 3D ß band (electron-type) (down to the 3rd Landau level). By investigating the angular dependence of the dHvA oscillations, we find that the frequencies and the corresponding Berry phase (ΦB) vary with the field direction, with a ΦB∼ 0 whenHis 10°-30° away from theabplane for both α and ß bands. The multiple band nature of PdTe2is further confirmed from Hall effect measurements.