Burban O. Deformation effects in (L1-Delta1)-model of conduction band of germanium crystals

This dissertation deals with the study of influence of a radical restructuring of the band structure of crystals n-Ge under significant uniaxial pressure on the mechanisms of tensoeffects and scattering of charge carriers. Constants of deformation potential, effective mass for density of states and tensor components of effective mass for Delta1-minimum were revealed on the basis of the theory of anisotropic scattering and experimental data of longitudinal tensoresistive effect of n-Ge crystals. The energy of ionization for the ground state of petty donors Sb, P, As for Delta1- model of the conduction band of single crystals n-Ge is calculated on the basis of variation method of Ritz taking into account chemical shift. The influence of (L1-Delta1) absolute minimum type of inversion on screening effect is investigated. The results of the investigation showed that screening radius for the same concentration of screening carriers is different for different type minima. The intervalley scattering should be taken into account in four-ellipsoidal and six-ellipsoidal Delta1-models of the n-Ge conduction band. Tensoresistive effect for uniaxially deformed along the crystallographic direction [100] single crystals n-Ge under different temperatures has been investigated. The results of theoretical calculations show that tensoresistive effect for n-Ge under uniaxial pressures 1,6<P<2,7 GPa depends on the effectiveness of nonequivalent intervalley scattering of electrons between L1- and Delta1-minima of the conduction band.