Conductivity of charge-ordered layered crystals in quantizing magnetic fields in the inversion region of the nonoscillating magnetoresistance component

The conductivity of charge-ordered layered crystals in electric and quantizing magnetic fields orthogonal to the layers is calculated. Charge ordering is considered as an alternation of layers with different charge-carrier densities. When scattering by acoustic phonons, conductivity is calculated in the approximation of profound quantization, so that the intersubband transitions can be assumed to be suppressed. It is shown that. in the transition of the layered crystal from the disordered to almost completely ordered state, the conductivity oscillations exhibit double periodicity. In this case, the high "carrier" frequency is controlled by the effective attractive electron-electron interaction responsible for charge ordering, whereas the low "modulation" frequency is defined by the width of the narrow miniband orthogonal to the layers. It is also shown that, in the transition from a disordered to an almost, completely ordered state, the longitudinal conductivity of layered crystals decreases by two or three orders of magnitude. At the same time, the relative contribution of oscillations sharply increases, with satisfactory agreement to the experimental data.