Spin splitting of the conduction band and de Haas–van Alphen effect inHg1−xFexSe

De Haas–van Alphen oscillations in ${\mathrm{Hg}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Fe}}_{\mathrm{x}}$Se in a magnetic field B directed along the [111] direction exhibit a beating pattern in which every third beat is anomalous. A semiclassical magnetic breakdown model is shown to describe these data in a satisfactory way provided the interaction of the electron magnetic moment with B is a small perturbation compared to the inversion-asymmetry-induced spin-orbit interaction.