Spin-orbit coupling and anomalous angular-dependent magnetoresistance in the quantum transport regime of PbS

We measured magnetotransport properties of PbS single crystals which exhibit the quantum linear magnetoresistance (MR) as well as the static skin effect that creates a surface layer of additional conductivity. The Shubnikov-de Haas oscillations in the longitudinal MR signify the peculiar role of spin-orbit coupling. In the angular-dependent MR, sharp peaks are observed when the magnetic field is slightly inclined from the longitudinal configuration, which is totally unexpected for a system with nearly spherical Fermi surface and points to an intricate interplay between the spin-orbit coupling and the conducting surface layer in the quantum transport regime.