Electronic Properties of High Temperature Superconductors

9801990阿尔马桑这个实验研究项目处于交通研究的前沿，以澄清铜酸盐的不寻常的正常状态性质。这项工作集中在面内和面外方向的电导各向异性，使用了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对掺杂、温度和磁场的依赖关系。这些数据将被分析以获取有关电子结构和传导机制的信息。研究了不同掺杂的YPrBa2Cu3O7和TlSr2LuCaCu2Oy单晶。C轴的传输机制将通过比较有无链的系统中的行为来研究。将寻找CuO链正常态光谱中可能存在的能隙的证据。在强非化学计量比(欠掺杂和过掺杂)的铜酸盐中，我们将通过磁场抑制超导电性来探索正常态的导电。其中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。这项工作有望促进对铜酸盐中正常态的导电性质和电子结构的深入了解。更广泛地说，这项基础研究的结果可能包括基本的新物理效应，还可能为适当的掺杂方案提供洞察，以促进铜酸盐在电子传感器或设备中的应用。这一高度跨学科的项目主要涉及少数族裔研究生，他们在两个实验室进行论文研究，并接受对未来在工业、政府或学术界的职业有益的优秀培训。这个实验研究项目是关于含有铜氧化物平面的金属氧化物的异常电学性质和行为。其中一些材料是高温超导体，例如YBa2Cu3O7，它的超导转变温度约为开尔文标度的92度。这些导电氧化物在高温或超导电性被外加磁场破坏时的“正常态”性质，是这项研究的主题。有人提出，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的电导体非常不同。阐明这些新的电学行为可能有助于这些材料最终在电子设备中的应用，如磁场传感器，甚至计算机逻辑设备。其中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。这一高度跨学科的项目主要涉及少数族裔研究生，他们在两个实验室进行论文研究，并接受对未来在工业、政府或学术界的职业有益的优秀培训。***

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. ***