Measurements of the quantum oscillations in the transverse magnetoresistance (Shubnikov–de Haas effect) at T=1.3 K as a function of magnetic field direction in ${\mathrm{Hg}}_{1\mathrm{-}\mathrm{x}}$${\mathrm{Fe}}_{\mathrm{x}}$Se with x=0.03 and 0.05 are reported. The oscillatory data are characterized by a number of zeros in the amplitude of the Shubnikov–de Haas oscillations. The angular anisotropy of the zero positions cannot be explained by existing Fermi-surface models. The position of these zeros is used to estimate the energy splitting in the conduction band of this material.

• Received 5 August 1985

DOI:https://doi.org/10.1103/PhysRevB.33.5585