Dvornyk O. The isoenergetic surface and the fundamental band parameters of А(ІІ)3В(V)2 compounds

This work is devoted to theoretical study of the energy spectrum of charge carriers and the kinetic effects of such characteristics as the state density, the effective mass of state density in modifications of А(ІІ)3В(V)2 compounds with a center and without a center of symmetry. Within the first approximation of perturbation theory band kp-model was generalized for А(ІІ)3В(V)2 uniaxial crystals. The hamiltonians for А(ІІ)3В(V)2 materials of different symmetry groups by the theoretical-group methods are construct. The generalized dispersion equation adequate for crystals with a center and without a center of symmetry, which takes into account nonparabolic and anisotropy of energy zones edge, is obtained. This dispersion equation describes the emergence of additional topological transitions for isoenergetic surfaces, the Van Hove singularities in the functional dependence of states density. The effective mass of state density of charge carriers near the extremes of zones are calculated. The direct and indirect effects of refined nonlinear functional relation between the crystal field parameter (parameter Kildal) and axial deformation of the lattice on energy spectrum of charge carriers are investigated. It was shown that the total spin split for all spin subzone for modifications without symmetry center is equal to zero if the parameter is not independent on tetragonal lattice deformation.