High Precision Landau Quantum Oscillation Measurements in the Normal and Mixed States of High-Temperature Superconductors

高温超导体正常状态和混合状态下的高精度朗道量子振荡测量

• 批准号: 9501419
• 负责人: Roy Goodrich
• 金额: $ 26万
• 依托单位: Louisiana State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-06-01 至 1999-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9501419&HistoricalAwards=false
• 关键词: Precision; Landau; Quantum; Oscillation; Measurements

9501419 Goodrich In this project, measurements of Landau quantum oscillations are made on high temperature superconductors in both the normal and the superconducting mixed states. Both epitaxial films of yttrium barium copper oxide and bismuth strontium rare-earth copper oxide, and bulk single crystals of other superconductors are studied. The physics investigated includes Fermi surface topologies, effective masses, and scattering rates for electrons in the normal state; the interaction of normal electrons with flux vortices in the mixed state; and the behavior of superconducting properties of high temperature superconducting materials in the presence of a strongly Landau- quantized normal-state background. The Fermi surface measurements in the normal state will give values for parameters that are crucial to theories of the mechanism of superconductivity in these materials. The mixed state results will lead to a much improved description of electron-electron and electron-flux vortex interactions. %%% One of the problems limiting the development of materials that exhibit truly high-temperature superconductivity (above the temperature of liquid nitrogen, -196 deg C) is that the basic mechanism responsible for high-temperature superconductivity remains unknown. The present work is directed toward gaining information about this mechanism in a variety of high-temperature superconductors by measuring fundamental properties of the electrons that participate in superconductivity, in both the super-conducting and normal (resistive) condition. By using strong magnetic fields and measuring the quantized magnetism of the electrons, precise values are obtained for parameters that are crucial to theories of superconductivity. This information can then be used to evaluate and test quantitatively these theories. The measurements are made using specialized facilities at the National High Magnetic Field Labo ratory, at Louisiana State University, and at Oak Ridge National Laboratory. ***

9501419 Goodrich在该项目中，在正常和超导混合状态的高温超导体上进行了Landau量子振荡的测量。研究了Yttrium钡铜氧化钡和二晶肌稀土铜的外延膜，以及其他超导体的散装单晶。 所研究的物理学包括正常状态的电子表面拓扑，有效质量和电子的散射率；正常电子与混合状态下通量涡流的相互作用； 以及在存在强烈量化的正常状态背景的情况下，高温超导材料的超导性能的行为。正常状态中的费米表面测量值将为这些材料中超导性机理至关重要的参数提供值。混合状态的结果将导致对电子电子和电子频率涡流相互作用的描述。 %% %%限制表现出真正高温超导性的材料发展的问题之一（高于液氮的温度，-196 d c）是，导致高温超导性的基本机制尚不清楚。 目前的工作旨在通过测量参与超导性的电子的基本特性，在超导和正常（电阻）条件下，通过测量参与超导性的电子的基本特性来获得有关这种机制的信息。通过使用强磁场并测量电子的量化磁性，对于对超导性理论至关重要的参数获得了精确值。然后，这些信息可用于定量评估和测试这些理论。 这些测量是在路易斯安那州立大学和橡树岭国家实验室的国家高磁场Labo Ratory的专业设施中进行的。 ***