Quantum Hall effect in layered InSe crystals

Quantization of the Hall resistance ρxy is observed in an investigation of the galvanomagnetic properties of bulk InSe crystals at temperatures 1.3 K≤T≤4.2 K and in fields H≤80 kOe. On the plateau the values of ρxy are close to h/ie2 (i=1, 2, ...) which are characteristic of the quantum Hall effect. Quantization of the Hall resistance is ascribed to the presence of plane defects in the bulk of the crystals. At low temperatures electrons are localized at the defects thus forming regions of a two-dimensional electron gas. Doubling of the quantum oscillation frequency is observed in fields H >or approx. 30 kOe; it is due to lifting of spin degeneracy of the Landau levels. It is proved that the two-dimensional electrons in InSe belong to the lowest minimum of the conductivity band located in the middle of the Brillouin zone