Theoretical Design of New Materials and Prediction of Electronic Structures and Properties of the Materials

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Many recent advances in condensed matter physics me due to vigorous interaction among physic material science and technology. Such interaction is schematically expressed by the corrlation diagra shown in Fig. 1. This correlation diagramindicates poss bilities towards 21st century that we can mak new materials according to our desires and the birth of such man made materials leads to discovery new phenomena and new physical concepts, and that new devices are invented from them.The purpose of the present research project was twofold:(1) to establish a theoretical framewor to calculate the electronic structures and the stability of such new materials and (2) to design a ne hypothetical stable material with use of the theory established by (1).Accelerated by perpetual desire to find concepts and new phenomena, we have chosen the followin eight categories of materials as the object of sutdy; (1) semiconductor ultrathin layered superlattice (2)semiconductor-metal superlattices, (3)graphite i … More ntercalation compounds, (4) doped semiconducto which exhibit a metal-insulator transition, (5) microclusters in a mesoscopic regime, (6) quasi-crystal (7) new material phases on surface, and (8) high temperature superconducting copper oxides.The outstanding results obtained by this project were the following: (1) the proposal and develop ment of spin-polaron pairing mechanism in high T_ccopper oxides, (2) the proposal and development intercalation compounds (GIC_s), (3) clarification of the origin of paramagnetic orbital susceptibilit of GIC_s, (4) elucidation of the origin of the NMR shift in GIC_s and graphite, (5) development of theoretical framework to treat the interplay between discover and electron-electron interaction in a Anderson-localized regime near the metal-insulator transition in doped semiconductors. (6) develop ment of new variational methods to treat many-body problems in new materials in a mesoscopic regim such as impurity clusters and metallic microclusters which are multiconfigulation self-consistent fie (MCSCF) method and floating ellipsoidal gaussian orbital (FEGO) method, (8) the electronic stru ture calculation of the new material phases on surfaces for MgO polar surface, Si(100)2X1/alkeli, an Si(100) reconstructed surface, (9) development of a the oretical framework to treat the dynamics an electronic attachment of miclocluster.As mentioned above, the group of the present research project has been working actively and ha accomplished a number of new interesting and important rnsults. Less