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Information × Registration Number 0309U007014, 0107U000663 , R & D reports Title Theoretical Modeling of Electronic Correlation Effects in Quasi-univariate Magnetic and Semi conductive Systems popup.stage_title Польові та температурні залежності електричних та магнітних властивостей квазіодновимірних моделей магнетиків Head Cheranovski Vladislav, Registration Date 21-01-2009 Organization Kharkov Natuional university named after V.N.Karazin popup.description2 Objects of the theoretical study is magnetic structure of nanostructures of spin ladder type and effect of acceptor admixtures and nanostructures geometry on their magnetic properties. The purpose of work is to perform detailed theoretical study of magnetic properties "ferrimagnetic" nanotubes and necklace spin ladder by means of perturbation theory and numerical calculations; to study effect of geometrical parameters and electron concentration on the energy spectrum and magnetic properties of the models. In this work the analysis of the energy spectrum and ground state spin structure of "ferromagnetic" nanotubes and necklace spin ladders with space anisotropy neighboring couplings was performed with the help of perturbation theory and numerical calculations by exact diagonalization study. It is shown the existence of the plateau in field dependence of nanotubes magnetization at the value of z-projection of total spin and low temperature due to gap character of the excitations with the increase oftotal spin. On the base of cyclic spin permutation formalism the effective spin Hamiltonians describing low-energy excitations of doped necklace ladders with weakly interacted unit cells were derived. It is shown, that the strong acceptor doping destroys the ferromagnetic ground state of the ladder. The effective algorithm of spin adaptation of CC equations for singlet states is derived on the base of unitary group generators technique. Product Description popup.authors popup.nrat_date 2020-04-02 Close