Study Of Electron Correlation And Polaron In One-dimensional Periodic Chain Of Organic Magnetic Superlattice

Conjugated organic polymer has been paid more and more attention as a novelfunctional material. A large number of studies have found that after nearly three decades,the polymer material has not only metals and semi-metallic nature, can be used asconductors and semiconductors, but also has its own easy processing, flexibility, goodfeatures. After nearly three decades, numerous studies found that the polymer materialnot only has the ease of processing, flexibility and good features, but also have metalsand semi-metallic nature, which can be used as conductors and semiconductors. Carrierin the organic conductive polymer material is not the traditional electron and hole, butthe soliton, polaron, bipolaron nonlinear original excitation. Only the neutral soliton andbelt single electric charge polaron carry spin, others don’t have. The characteristics ofquasi-one-dimensional polymer, especially its rich electric, magnetic, optical and othercharacteristics already have an accurate understanding. The results obtained by thetheoretical model and experimental results are coincide.Establish theoretical model of polymer through a process of continuousimprovement. SSH model has made a great contribution to the study of organicpolymers. In order to study the ground state of nondegenerate polymers and considerthe impact of e-electron interactions KSSH model and the extended SSH modelestablished based on the original SSH model. In recent years, it was found that electroncorrelation has a great influence on the nature of the electronic states in the polymer andthe carrier. Zhao guide for the first time launched a long-range correlation Hamiltonianand the analytic formulas of long-range correlation energy, which is of greatsignificance for the study of electron correlation.Due to the discovery of giant magneto-resistance and tunnel magneto-resistance inrecent years, triggered a revolution in magnetic storage and magnetic recording, and theresulting new discipline around the spin transport and injection control-spintronics. Asthe organic semiconductor material with the hyperfine interaction and the weakspin-orbit coupling, spin diffusion length is relatively long, so it is an ideal candidatematerial for spin-polarized transport. The study of organic spintronics has profoundimplications for understanding the physical properties of organic materials, to exploreits features and value. Carriers in organic semiconductor materials and inorganicsemiconductor materials are essentially different. The carriers in organic semiconductor materials are not traditional electron or hole, but rather the soliton, polaron, bipolaron,only neutral solitons and polaron carrying spin. As for stability about polaron andbipolaron in organic materials, there has been existing controversy.The content and main conclusions of this scholar thesis are as follows：(1) The object of study is trans-polyacetylene, consider the electron–electroninteractions and long-range electron correlation on the basis of the SSH model. Ourmain study is Long-range electron correlation on the polymer electronic states and thepolaron shape. Found by calculating: Compared to not consider long-range electroncorrelation polaron deformation and the polaron regional broadening; The long-rangeelectron correlation weakened the polaron regional charge density oscillations; Wefound that through the calculation of the electronic polaron and hole polaron，electronicpolaron correlation energy bigger than the ground state, while the hole polaron issmaller than the ground state.(2) In the fourth chapter, we have adopted a classical ferromagnetic metal/polymer/ferromagnetic metal structure，mainly study the factors affecting the polymer chargeinjection and spin polarization. We compared have electronic interaction and noelectronic interaction, found that the electronic interaction is more conducive to spinpolarization, but hinder charge injection. In addition, we also compared both ends of theferromagnetic material parallel and antiparallel, found that if electrons injected into theorganic matter, will form a unipolar when spin parallel and found spin polarization;Bipolaron format if spin anti-parallel, there is no spin polarization in the polymer.