Strongly Correlated Electron Phase under Multiple Environment

多环境下强相关电子相位

• 批准号: 10CE2004
• 负责人: MIYAKE Kazumasa
• 金额: $ 720.64万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for COE Research
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10CE2004/
• 关键词: heavy electron systems; anisotropic superconductivity; pressure induced superconductivity; ultra-high pressure induced metal-insulator; mesoscopic systems; nonlinear optics; photoinduced phase transition; Transport phenomena in low dimensional syst

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

研究方向包括以下三个主题：[1]强相关电子的性质，[2]受限系统中的相关电子相，以及[3]超高压下的电子相。[1]强相关电子的性质(Miyake, Kitaoka, OnuK, Suga)发现了由于临界价态涨落而实现超导的新机制，提出了Uge_2、Upd_2Al_3、PrOs_4Sb_<12>、(TMTSF)_2PF_6以及CeCu_2Si_2和CeCu_2Si_2相超导的新型机制。 CeRhIn_5与反铁磁性共存（Miyake）。利用NMR/NQR技术，研究了重费米子(Upt_3和Uni_2Al_3)和钌酸盐氧化物(Sr_2RuO_4)体系中的自旋三重态超导性，重费米子化合物在压力下的反铁磁性和超导性的微观共存相，纳米尺度的共存相。 多层高温超导体中的反铁磁性和超导性已被发现（Kitaoka）。已经生长出超过 50 种高质量的单晶铈和铀化合物，并且它们的磁性和费米表面特性已得到澄清（Onuki）。稀土和过渡金属化合物的高分辨率（能量和波矢量）软X射线光电子能谱在世界上首次获得成功，体敏感技术（Suga）的这一突破解决了并将解决许多争议。 [2]受限系统中的相关电子相位（Itoh、Cho、Hiyamizu、One、Okawa、Nozue）在强和弱约束状态下，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性，并发现了受限系统中电子相关性及其与光学非线性关系的证据。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”的新理论方案已得到高度发展，并应用于纳米结构和相关系统（Cho）中的各种线性和非线性过程。演示了在 (775)B GaAs 衬底上 MBE 生长的 In_<0.1>Ga$_<0.9>As/(GaAs)_6(AlAs)_1 量子线 (QWR) 激光器的室温振荡，发射波长范围为 0.85μ，并制备了极其均匀的 (221)A In_<0.22>Ga_<0.78>As/GaAs 量子线 （桧水）。为了创造基于自旋极化电流的新效应，通过自旋极化电流对亚锰矿的磁阻控制、从铁磁体到超导体的自旋注入以及电流引起的磁畴壁运动进行了实验研究（小野）。从理论上研究了“光致相变”，以阐明多电子系统光激发非平衡态中的相分离动力学、经典和量子级的形成以及量子多体效应对线性/非线性光学响应的​​影响（小川）。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被发现受到约束势的强烈影响，并且发现沸石中碱金属簇的轨道简并性对其铁磁性起着重要作用（Nozue）。 [3]超高压下的电子相（Suzuki、Nasu、Shimizu、Kobayashi）首次证明固体氧中压力诱导的绝缘体-金属转变可以通过能带重叠来实现（Suzuki）。已经进行了高压^<57>Fe穆斯堡尔测量，阐明了作为金属Fe(Nasu)的高压相的ε-Fe的磁性。产生极低温和超高压以及测量物理性质的技术已经开发出来，并且在简单的系统中发现了压力下的超导性，例如氧、铁、锂和有机分子晶体、离子晶体等（清水）。通过新开发的高压池，在U基和Ce基重电子化合物中发现了压力诱导的磁-非磁转变、超导性和电荷排序，特别是在铁磁超导体Uge_2中，超导性的体质性质是通过热容测量确定的（Kobayashi）。较少的

项目成果

K.Fujii: "Time resolved Far-infrared Magneto-optical Absorption of a Quantum Dot Array" Solid State Electronics. 42. 1349-1353 (1998)

K.Fujii：“量子点阵列的时间分辨远红外磁光吸收”固态电子学。

K.Sugiyama et al.: "Metamagnetic transition in UPt_3 studied by high-field magnetization and de Haas-van Alphen experiments"Phys.Rev.B. 60. 9248-9251 (1999)

K.Sugiyama 等人：“通过高场磁化和 de Haas-van Alphen 实验研究 UPt_3 中的变磁转变”Phys.Rev.B。

Y.Haga, et al.: "Quasi-two dimensional Fermi surfaces of the heavy fermion superconductor CeIrIn_5"Phys.Rev.B. 63. 060503(R)-(1-4) (2001)

Y.Haga 等人：“重费米子超导体 CeIrIn_5 的准二维费米面”Phys.Rev.B。

R.Jung: "Temperature dependent bulk sensitive Ce 3d edge resonant photoemission study of CeFe_2"J.Electron Spectrosc.Rel.Phenom.. 114-116. 693-698 (2001)

R.Jung：“CeFe_2 的温度依赖性体积敏感 Ce 3d 边缘共振光发射研究”J.Electron Spectrosc.Rel.Phenom.. 114-116。

K.Soda: "Magnetic circular dichroism at transition metal L_<2,3> edges in Do_3 -type(Fe_<1-x>V_x)_3 Al Alloys"J.Synchrotron Rad.. 8. 455-456 (2001)

K.Soda：“Do_3 型(Fe_<1-x>V_x)_3 铝合金中过渡金属 L_<2,3> 边缘的磁圆二色性”J.Synchrotron Rad.. 8. 455-456 (2001)