Electronic structures of the systems with orbital degeneracy

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We have grown high quality samples of the systems where the orbital degrees of freedom play important roles and have revealed their electronic structures. The samples were also supplied to the other research groups of the present project to perform the research using various methods.1. We have revealed characteristic electronic structures of high Tc compound MgB_2 and its related compound AlB_2 using photoemission spectroscopy and soft X-ray emission and absorption spectroscopy.2. We have studied the anomalous magnetic properties and electronic structures of high-temperature weak ferromagnet CaB_6 employing various methods such as magnetic measurements, ESR, photo emission spectroscopy, SdH effect. Most of the experimental results previously reported have been found to be incorrect. We have also performed a detailed analysis of magnetic impurities, but could not clarified whether or not the weak ferromagnetism is intrinsic.3. We have revealed anomalous changes of the magnetic phase diagrams and electronic structures with hydrostatic and uniaxial pressures for the systems with quadrupolar order, CeB_6, PrPb_3 and Ce_3Pd_<20>Ge_6.4. We have revealed the electronic structures of the conduction electrons and magnetic interactions among magnetic ions by SdH effect and NMR measurements for the compounds like Yb_4As_3 and their alloys where the charge order transition takes place at high temperatures.5. We have revealed anomalous magnetic properties and electronic structures of the U compounds like Upd_3 and U_3Pd_<20>Si_6 whose 5f electrons show localized nature.6. We have also performed extensive studies on other important systems such as RB_2C_2, RB_6, TmTe, rare earth chalcogenides, rare earth pnictides and uranium compounds.