Klysko Y. Electronic, optical and magnetic properties of metal-organic frameworks as promising materials of nanoelectronics and nanospintronics

The dissertation is devoted to the investigation of the electronic structure of metal-organic frameworks, their optical and magnetic properties in order to obtain characteristics that can be used in the development of elements of nanoelectronics and spinotronics. In the first section of the thesis ab initio quantum methods of evaluating electronic, optical and magnetic properties of materials are described. Single-particle approximations of the exchange-correlation potential are presented. Physical and mathematical feature of these methods are described, as well as the advantages and disadvantages of each of the approaches are indicated. The analysis of the Green's function based quasiparticle methods (the GWA method and the Bethe-Salpeter equation) is performed. This section also describes methods of studying of magnetic properties - ground-state calculations of spin polarized systems and the Heisenberg model. The implementation features of these methods and approximations in the ABINIT code are presented. The second section contains four subsections devoted to the electronic structure investigation of metal-organic nano-objects, namely transition metal phthalocyanines,hexaminobenzene- and hexaamintriphenylene-based two-dimensional complexes, pyrazinedithiolate-based coordination polymers, metal-organic framework MOF-74. A brief literature review of materials properties and their application in electronics is presented in each subsection. The features of calculations (methods and approximations , input parameters) are described. Magnetic properties of transition metal phthalocyanines have been studied. The electronic energy structure and the imaginary part of the dielectric function are obtained taking into account strongly correlated d-electrons and exciton effects. Electronic and optical properties of para- and ferromagnetic manganese, iron and cobalt phthalocyanines are obtained.The electronic energy spectrum and partial density of states in hexaaminobenzene- and hexaminetriphenylene-based two-dimensional metal-organic ano-objects are calculated. The electronic properties of pyrazinedithiolate-based coordination polymers are presented. The impact of strongly correlated d-electrons of transition elements is taken into account. These compounds were determined to be degenerate p-type semiconductors. The frequency dependence of the real and imaginary part of the dielectric function is calculated. The study of para-, ferro- and antiferromagnetic states in the transition metal containing metal -organic framework MOF-74 has been performed. Temperature dependences of magnetization and magnetic susceptibility are obtained. The electronic energy spectrum was calculated, taking into account the strong correlations of d-electrons, for each magnetic state. The frequency dependences of the real and imaginary part of the dielectric function are obtained.