New Phase of Matter in Multidisciplinary Approach

多学科方法的新阶段

基本信息

批准号：
15GS0213
负责人：
KITAOKA Yoshio
金额：
$ 376.31万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Creative Scientific Research
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2007
项目状态：
已结题

项目摘要

Our main objectives have established new concepts in materials science through the elucidation of the new phases of matter that underlies the superconductivity and magnetic ordering in strongly correlated matter, and the creation of unique materials, by measuring the properties of the materials in multidisciplinary approach. We list up the remarkable results obtained by this project.1. The discovery of the uniformly coexisting phase of antiferromagnetism (AFM) and superconductivity (SC) in a single CuO_2 layer has lead us to uncover their genuine phase diagram including an AF quantum critical point, which significantly differs from the previously believed phase diagrams as the function of carrier doping level for high-T_c copper-oxides superconductors.2. A tetracritical point in the temperature(T)-pressure(P) phase diagram of the heavy-fermion (HF) compound CeRhIn_5 was unraveled against the previous research results.3. The coexistence phase of ferromagnetism and SC was identified in UGe_2 around a quantum first-order phase transition.4. Novel pressure-induced superconductors CeNiGe_3 and Ce_2Ni_3Ge_5 were discovered.5. The discovery of the pressure-induced SC of HF compounds without inversion symmetry, such as UIr and CeIrSi_3 has pointed to the possibility of a new and unique superconducting state.6. Miyake, et. al. have been able to explain the appearance of high-T_c SC for HF compounds with the sudden change in the. valence number of Ce upon the application of pressure, by a novel anisotropic SC mechanism triggered by the critical valence number fluctuation.These remarkable findings on the new phases of strongly correlated matter would lead us to a coherent understanding of the mechanism of unconventional SC in HF compounds and high-T_c superconductors which is a long-term issue since their discoveries.

我们的主要目标是通过阐明强相关物质中超导性和磁有序性背后的物质新相，建立材料科学的新概念，并通过多学科方法测量材料的特性来创造独特的材料。我们列出了该项目所取得的显着成果： 1．在单个 CuO_2 层中均匀共存的反铁磁性（AFM）和超导（SC）相的发现使我们揭示了它们的真实相图，包括 AF 量子临界点，这与之前认为的相图显着不同，因为函数高T_c氧化铜超导体的载流子掺杂水平的研究；2．结合前人的研究成果，揭示了重费米子(HF)化合物CeRhIn_5的温度(T)-压力(P)相图中的四临界点。 3．在UGe_2中，在量子一级相变附近发现了铁磁性和SC共存相。4．发现了新型压感超导体CeNiGe_3和Ce_2Ni_3Ge_5。 5． UIr和CeIrSi_3等不具有反演对称性的HF化合物的压力诱导超导的发现，指出了一种新的、独特的超导态的可能性。6．三宅等。等人。已经能够解释 HF 化合物的高 T_c SC 的出现与突然的变化。通过由临界价数波动触发的新型各向异性 SC 机制，我们可以在施加压力时改变 Ce 的价数。这些关于强关联物质新相的显着发现将使我们对 HF 中非常规 SC 的机制有一个连贯的理解化合物和高温超导体，这是自他们发现以来的一个长期问题。