Abstract
Measurements of the quantum oscillations in the transverse magnetoresistance (Shubnikovde Haas effect) at T=1.3 K as a function of magnetic field direction in Hg1x FexSe with x=0.03 and 0.05 are reported. The oscillatory data are characterized by a number of zeros in the amplitude of the Shubnikovde 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.