Systematic Study of Structural Phase Transitions based on a New Electron Theory of Solids

基于新固体电子理论的结构相变系统研究

• 批准号: 60540226
• 负责人: MACHIDA Kazushige
• 金额: $ 1.47万
• 依托单位: Kyoto University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1985
• 资助国家: 日本
• 起止时间: 1985 至 1987
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60540226/
• 关键词: incommensurate phase; charge density wave; quasi-periodic system; heavy electron materials; superconductivity; 反強磁性; 不整合電荷密度波; ソリトン格子; 準周期性; 準位間隔の分布則; P-波超伝導; スピン密度波

We have investigated the following two subjects in this period: The first subject is the electron problem in low dimenstional materials, namely electronic states in incommensurate charge density waves (CDW) are studied, focusing on its energy gap structure. We have found a peculier gap structure characteristic of incommensurability. We also studied CDW under applied fields and the spin-peierls systems under high fields. Numerical calculations on quasi-periodic systems have been done in connection with the incommensurability problem to know the localization in this system. We have obtained a new power law behavior in the eigenvalue distribution.The second subject is the superconductivity in heavy electron materials. In order to uncover the nature of the exotic superconducting pairing states observedwe have considered the relationship between superconductivity and antiferro-magnetism and we have classified group-theoretically possible pairing states. By combining these two methods most plausible pairing states realized in UPt_3, UBe_<13> and URu^2Si_2 are enumerated. This prediction should be checked experimentally in near future.We have proposed a mechanism for high-Tc in recent oxide superconductors which shares common feature as a highly correlated system with the above heavy electron materials.

第一个课题是低维材料中的电子问题，即研究了无公度电荷密度波（CDW）中的电子态，重点研究了它的能隙结构。我们发现了一个更大的间隙结构，具有不可逆性的特点。我们还研究了外加场下的CDW和高场下的自旋-Peierls系统。为了研究准周期系统的局域化问题，对准周期系统的不可约性问题进行了数值计算。第二个课题是重电子材料的超导电性。为了揭示奇异超导配对态的本质，我们考虑了超导性和反铁磁性之间的关系，并对群论上可能的配对态进行了分类。结合这两种方法，计算了UPt_3、UBe_2和URu^2Si_2中最可能的配对态<13>。我们提出了一种氧化物超导体的高Tc机制，它与上述重电子材料具有高度关联的共同特征。

项目成果

K.MACHIDA: "Soliton Lattice Structure and Midgap Band in Nearly Commensurate Charge-Density-Wave States.II" Phys. Rev.B34. 5073-5081 (1986)

K.MACHIDA：“几乎相称的电荷密度波状态中的孤子晶格结构和中隙带。II”物理。

M.Fujita: "Spin Density Waves in Cr and cr-rich Cr-Mn and Cr-V alloys" J. Magn. Magn. Mater.70. 442-444 (1987)

M.Fujita：“Cr 和富铬 Cr-Mn 和 Cr-V 合金中的自旋密度波”J. Magn。

藤田光孝: Solid State Commun.59. 61-65 (1986)

藤田光隆：固态通讯59（1986）。

M.OZAKI: Prog.Theor.Phys.75. 442-444 (1986)

毛崎：Prog.Theor.Phys.75。

K.MACHIDA: J.Phys.Soc.Jpn.55. 1799-1801 (1986)

K.MACHIDA：J.Phys.Soc.Jpn.55。