Electronic Properties of High Temperature Superconductors

w：\awards\awards96\*.doc 9801990 Almasan 这个实验研究项目是在运输研究的最前沿，以澄清铜酸盐的不寻常的正常状态属性。 工作的重点是各向异性的导电 在平面内和平面外方向上， 使用极高质量和良好表征的掺杂铜酸盐单晶。PI将测量这些电导率各向异性的掺杂、温度和磁场依赖性。 这些数据将被分析以获得有关电子结构的信息 和 传导机制 单个 晶体 YPrBa_2Cu_3O_7和TlSr_2LuCaCu_2O_y的变化。通过比较有链和无链系统中的行为，研究C轴传输机制。 证据将寻求一个可能的能隙中的正常状态的光谱的CuO链。在强非化学计量比（欠掺杂和过掺杂）铜氧化物的正常态导电将被探测与磁场抑制超导电性。 部分工作将在佛罗里达州塔拉哈西的NSF支持的国家高磁场实验室进行。这项工作预计将推进对正常状态传导特性和电子结构的基本理解。 铜酸盐 更广泛地说， 基础研究可以包括基本的新物理效应，并且还可以提供对适当掺杂方案的深入了解，以促进铜酸盐用于电子传感器或器件的应用。 这个高度跨学科的项目强烈涉及少数群体的研究生谁追求论文研究在这两个 实验室位置，并获得优秀的 对将来在工业、政府部门工作有益的培训 或者学术界 这个实验研究项目是关于含有氧化铜平面的金属氧化物的不寻常的电性能和行为。这些材料中的一些是高温超导体，例如YBa2Cu3O7，其在开尔文标度上具有约92度的超导转变温度。这些导电氧化物在高温下或当超导性被外加磁场破坏时的“正常态”性质是本研究的主题。有人认为，即使在正常状态下，这些材料的导电方式也与铜和硅等典型导电体截然不同。阐明这些新颖的电学行为可能有助于这些材料在电子器件中的最终应用，例如磁场传感器甚至计算机逻辑器件。一些工作将在佛罗里达州塔拉哈西的NSF支持的国家高磁场实验室进行。这个高度跨学科的项目涉及少数民族研究生，他们在两个实验室进行论文研究，并接受良好的培训，有利于未来在工业，政府或学术界的职业生涯。 ***

w:\awards\awards96\*.doc 9801990 Almasan This experimental research project is at the forefront of transport studies to clarify the unusual normal state properties of cuprates. The work focuses on anisotropy of electrical conduction in in-plane and out-of-plane directions, using extremely high quality and well-characterized single crystals of doped cuprates. The PI will measure the doping, temperature and magnetic field dependences of these conductivity anisotropies. The data will be analyzed for information about electronic structure and conduction mechanisms. Single crystals of YPrBa2Cu3O7 and TlSr2LuCaCu2Oy of variable dopings will be investigated. C-axis transport mechanisms will be investigated by comparing behavior in systems with and without chains. Evidence will be sought for a possible energy gap in the normal state spectrum of the CuO chains. Normal state conduction in strongly off-stoichiometry (under-doped and over-doped) cuprates will be probed by suppressing superconductivity with magnetic fields. Some of the work will be carried out at the NSF-supported National High Magnetic Field Laboratory in Tallahassee FL. This work is expected to advance fundamental understanding of the normal state conduction properties and electronic structure in the cuprates. More broadly, the results from this basic investigation may include fundamental new physical effects and also may provide insight into appropriate doping schemes to facilitate applications of cuprates for electronic sensors or devices. This highly interdisciplinary project strongly involves minority-group graduate students who pursue thesis research at both laboratory locations, and receive excellent training beneficial to a future career in industry, government or academia. %%% This experimental research project is concerns the unusual electrical properties and behavior of metallic oxides containing copper oxide planes. Some of these materials are high temperature superconductors, for example YBa2Cu3O7 which has a superconducting transition temperature of about 92 degrees on the Kelvin scale. The "normal state" properties of these conducting oxides at high temperatures or when the superconductivity is destroyed by an applied magnetic field, are the topics of this research. There are suggestions that these materials, even in the normal state, conduct electricity in ways that are very different from typical electrical conductors such as copper and silicon. Clarifiying these novel electrical behaviors may contribute to eventual applications of these materials in electronic devices such as magnetic field sensors or even computer logic devices. Some of the work will be carried out at the NSF-supported National High Magnetic Field Laboratory in Tallahassee FL. This highly interdisciplinary project strongly involves minority-group graduate students who pursue thesis research at both laboratory locations, and receive excellent training beneficial to a future career in industry, government or academia. ***