Quantitative evaluation of Dirac physics in PbTe

The magnetic field dependence of electronic transport, magnetic, and elastic properties in single crystals of PbTe were investigated in high magnetic fields up to 55 T. The magnetoresistance, magnetization, ultrasonic attenuation, and sound velocity showed clear quantum oscillations with pronounced Zeeman-splitting, which causes a large second harmonic in the frequency spectra. The ratio of the Zeeman to the cyclotron energy, which is regarded as an index of `Diracness' [H. Hayasaka and Y. Fuseya, J. Phys.: Condens. Matter \textbf{28,} 31LT01 (2016).], was determined to be 0.52 and 0.57 in samples with different carrier densities. We also pointed out that the effect of Zeeman-splitting seriously affects the Landau-level fan diagram analysis, which is widely used to extract the nontrivial Berry's phase from the quantum oscillations.