Fig. 2.

Angle-dependent quantum oscillations. a The MR data from b-axis ribbon obtained at different angles and T = 2 K. b The d² R/dB ²data obtained from a clearly shows quantum oscillations. c The evolution of quantum frequency in FFT spectra obtained from b as the angle increases. The arrow indicates the evolution of the peaks. d Angle dependence of extracted Weyl orbit frequency. It shows a ${cos}^{-1}\theta$ dependence (solid line), indicating a 2D surface state. The error bar of 20%, including standard instrument error and FFT frequency spacing estimate, was added into the angular dependence of frequency