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Electronic structures of the systems with orbital degeneracy

轨道简并系统的电子结构

基本信息

批准号：
11220203
负责人：
AOKI Haruyoshi
金额：
$ 58.88万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

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.

我们已经生长出高质量的样品的系统中的轨道自由度发挥重要作用，并揭示了它们的电子结构。本研究亦将样本提供给本计画的其他研究小组，以进行不同方法的研究。利用光电子能谱、软X射线发射光谱和吸收光谱揭示了高Tc化合物MgB_2及其相关化合物AlB_2的特征电子结构.本文采用磁性测量、ESR、光电子能谱、SdH效应等方法研究了高温弱铁磁体CaB_6的反常磁性和电子结构。以前报道的大多数实验结果都被发现是不正确的。我们还对磁性杂质进行了详细的分析，但无法澄清弱铁磁性是否是固有的。我们揭示了四极系统CeB_6，PrPb_3，Ce_3Pd_Ge_6.4的磁相图和电子结构随流体静压和单轴压力的反常变化<20>。通过对Yb_4As_3等化合物及其合金的SdH效应和NMR测量，揭示了高温下发生电荷序跃迁的导电子的电子结构和磁性离子间的磁相互作用.我们揭示了Upd_3和U_3Pd_Si_6等铀化合物的反常磁性和电子结构<20>，它们的5f电子具有局域性质.我们还对其它重要体系如RB_2C_2、RB_6、TmTe、稀土硫属化合物、稀土磷属化合物和铀化合物进行了广泛的研究。