Strongly Correlated Electron Phase under Multiple Environment

[1]强相关电子的性质，[2]受限系统中的相关电子相，[3]超高压下的电子相发现了由临界价涨落引起的超导新机制，提出了Uge_2、Upd_2Al_3、PrOs_4Sb_<12>、（TMTSF）_2PF_6以及CeCu_2Si_2和CeRhIn_5与反铁磁性共存相（Miyake）的超导新机制。利用NMR/NQR技术，发现了重费米子（Upt_3和Uni_2Al_3）和氧化钌酸盐（Sr_2RuO_4）体系的自旋三重态超导性，重费米子化合物在压力下反铁磁性和超导性的微观共存相，多层高温超导体中反铁磁性和超导性的纳米级共存（Kitaoka）。高质量的单晶…铈和铀化合物的数量超过50个，并且它们的磁性和费米表面性质已经被澄清（Onuki）。稀土和过渡金属化合物的高分辨率（能量和波矢量）软x射线光谱学在国际上首次获得成功，体敏技术的突破解决了许多争议（Suga）（Itoh, Cho, Hiyamizu, One, Ogawa, Nozue）在强约束和弱约束条件下，研究了激子能量和寿命对单个纳米结构中激子数量的依赖关系，并发现了约束系统中电子相关的证据及其与光学非线性的关系。验证了相关光子系统中光子德布罗意波长的概念（Itoh）。“物质的微观非局域光学响应”这一新的理论方案得到了高度发展，并应用于纳米结构和相关系统中的各种线性和非线性过程（Cho）。在（775）B GaAs衬底上，制备了波长范围为0.85μ的（221）A In_<0.22>Ga_<0.78>As/GaAs量子线（QWR）激光器（Hiyamizu）。为了创造基于自旋极化电流的新效应，实验研究了自旋极化电流对锰矿石的磁阻控制、铁磁体向超导体的自旋注入以及电流诱导的畴壁运动（Ono）。对“光致相变”进行了理论研究，阐明了多电子系统光激发非平衡态中相分离动力学、经典序和量子序的形成以及量子多体效应对线性/非线性光学响应的影响（Ogawa）。整数和分数量子霍尔系统中边缘态的空间分布和电子输运现象受约束势的强烈影响，沸石中碱金属团簇的轨道简并对其铁磁性起重要作用（Nozue）超高压下的电子相（Suzuki, Nasu, Shimizu, Kobayashi）首次证明了固体氧中压力诱导的绝缘体-金属过渡可以通过能带重叠实现（Suzuki）。对金属铁（Nasu）的高压相ε-Fe进行了穆斯堡尔测量，明确了其磁性能。超低温超高压的产生和物理性质的测量技术已经发展起来，在简单的体系中，如氧、铁、锂和有机分子晶体、离子晶体等，发现了超压下的超导性（Shimizu）。利用新开发的高压电池，在U-和ce基重电子化合物中，特别是在铁磁超导体Uge_2中，发现了压力诱导的磁-非磁跃迁、超导性和电荷有序性，并通过热容测量确定了超导性的块状性质（Kobayashi）。少

Research was performed in the following three subject : [1] Properties of strongly correlated electrons, [2] Correlated electron phase in confined systems, and [3] Electron phases under ultra-high pressures.[1] Properties of strongly correlated electrons (Miyake, Kitaoka, OnuK, Suga)New mechanism of superconductivity of due to critical valence fluctuations is found, new types of mechanism are proposed for superconductivity in Uge_2, Upd_2Al_3, PrOs_4Sb_<12>, (TMTSF)_2PF_6, and the phase of CeCu_2Si_2 and CeRhIn_5 coexisting with the antiferromagnetism (Miyake). By means of NMR/NQR techniques, spin-triplet superconductivity in heavy-fermion (Upt_3 and Uni_2Al_3) and rutenate oxide (Sr_2RuO_4) systems, microscopic coexisting phase of antiferromagnetism and superconductivity in heavy-fermion compounds under pressure, a nano-scale coexistence of antiferromagnetism and superconductivity in multilayered high-temperature superconductors, have been discovered (Kitaoka). High-quality single cry … More stals of cerium and uranium compounds over fifty in number have been grown, and their magnetic and Fermi-surface properties have been clarified (Onuki). High resolution (energy and wave vector) soft X-ray photoemision spectroscopy of rare earth and transition metal compounds have been succeeded for the first time in the world, and many controversies are solved and going to be solved by this break through of the bulk sensitive technique (Suga).[2] Correlated electron phase in confined systems (Itoh, Cho, Hiyamizu, One, Ogawa, Nozue)Both in the strong and weak confinement regimes, the dependencies of exciton energy and life time upon the number of excitons in a single nano-structure were studied and the evidence of electron correlation in confined systems and its relation with optical nonlinearities were found. The concept of photonic de Broglie wavelength in correlated photon system was verified (Itoh). A new theoretical scheme of "microscopic nonlocal optical response of matter" has been highly developed and applied to various linear and nonlinear processes in nanostructures and related systems (Cho). Room temperature oscillation of MBE-grown In_<0.1>Ga$_<0.9>As/(GaAs)_6(AlAs)_1 quantum wire (QWR) lasers on (775)B GaAs substrates with an emission wavelength range of 0.85μ was demonstrated, and extremely uniform (221)A In_<0.22>Ga_<0.78>As/GaAs quantum wires were fabricated (Hiyamizu). For the purpose of creating novel effects based on spin-polarized current, magnetoresistive control of a manganite by spin-polarized current, spin injection from ferromagnet into superconductor, and current-induced domain wall motion were studied experimentally (Ono). "Photoinduced Phase Transition" was studied theoretically to clarify the phase-separation dynamics, formation of classical and quantum orders, and quantum many-body effects on linear/nonlinear optical responses in photoexcited nonequilibrium states of many-electron systems (Ogawa). The spatial distribution and the electron transport phenomena of edge state in integer and fractional quantum Hall system are found to be strongly affected by the confinement potential, and an orbital degeneracy of alkali metal clusters in zeolite is found to play an important role for its ferromagnetism (Nozue).[3] Electron phases under ultra-high pressures (Suzuki, Nasu, Shimizu, Kobayashi)It has been shown for the first time that the pressure-induced insulator-metal transition in solid oxygen would be realized by band overlapping (Suzuki). High pressure ^<57>Fe Mossbauer measurements have been performed, clarifying the magnetic property of ε-Fe which is a high-pressure phase of metallic Fe (Nasu). Techniques of generating very low-temperature and ultra high-pressure and measuring physical properties have been developed, and superconductivity under pressure was discovered in simple systems, such as oxygen, iron, lithium and organic molecular crystals, an ionic crystal, etc. (Shimizu). By means of newly developed high-pressure cell, the pressure-induced magnetic-nonmagnetic transition, superconductivity and charge-ordering have been found in the U- and Ce-based heavy electron compounds, particularly in the ferromagnetic superconductor Uge_2, the bulk nature of the superconductivity was established by the heat capacity measurements (Kobayashi). Less