Investigation of the Low Temperature Normal State of Electron-Doped Copper Oxides

了解铜酸盐的高温超导电性机制是凝聚态物理中尚未解决的主要问题之一。个人研究者奖的主要目的是更详细地了解电子掺杂高T_c铜酸盐的正常态性质，并将这些性质与更多研究的空穴掺杂铜酸盐进行比较/关联。提出了一套综合的实验方案，用于研究磁场抑制超导电性时的低温正常态。对低温正常态性质的理解有望为理解高温超导电性的起源提供重要信息。本研究中使用的实验技术包括：各向异性输运(即电阻率、霍尔效应、磁阻、能斯特效应、热电势和热导率)、比热和隧道效应。与其他小组的合作实验将使用拉曼散射、红外光学、核磁共振和Muon自旋共振。所有这些实验所需的晶体和薄膜将被制备并用等电点进行表征。该计划的更广泛的影响包括培养本科生、研究生和博士后科学家进行材料物理研究，特别是薄膜生长、表征和传输测量的方法学。了解高温超导(即在液氮沸点以上的温度下的超导电性)的起源是物理学中尚未解决的主要问题之一。该个人研究人员奖支持一个项目，该项目通过对一组特别挑选的氧化铜高温超导体的电传输特性进行全面研究来解决这一问题。测量将在强磁场和非常低的温度下进行。拟议中的研究将探索与传统金属和超导体相比高度反常的性质。因此，这一研究结果可能为研究高温超导电性的机制提供重要的新见解。这些研究还有望为这些新材料的科学和技术开辟新的途径，以及为强相互作用电子主导物理的其他材料开辟新的道路。该项目还涉及材料物理领域的本科生、研究生和博士后科学家的培训，这是一个具有重要技术意义的领域。

Understanding the mechanism of high-Tc superconductivity in the cuprates is one of the major unsolved problems of condensed matter physics. The main goal of this Individual Investigator Award is to gain a more detailed understanding of the normal state properties of the electron-doped high-Tc cuprates and to compare/relate these properties to the more studied hole-doped cuprates. A comprehensive set of experiments is proposed that will study the low temperature normal state when the superconductivity is suppressed by a magnetic field. An understanding of the properties of the low temperature normal state is expected to give crucial information for understanding the origin of high-Tc superconductivity. The broad ranges of experimental techniques to be used in this study are: anisotropic transport (i.e., resistivity, Hall effect, magnetoresistance, Nernst effect, thermopower, and thermal conductivity), specific heat, and tunneling. Collaborative experiments with other groups will use Raman scattering, IR optics, NMR, and muon spin resonance. The crystals and thin films needed for all of these experiments will be prepared and characterized by the PI. The broader impact of this program includes the training of undergraduate science majors, graduate students, and postdoctoral scientists in materials physics research, especially the methodology of thin film growth and characterization and transport measurements.Understanding the origin of high-temperature superconductivity (i.e., superconductivity at a temperature, Tc, above the boiling point of liquid nitrogen) is one of the major unsolved problems of physics. This Individual Investigator Award supports a project that addresses this problem by a comprehensive study of the electrical transport properties of a specially selected group of copper oxide high-Tc superconductors. The measurements will be made in high magnetic fields and at very low temperatures. The proposed studies will probe properties that are highly anomalous in comparison with conventional metals and superconductors. Therefore, the results of this study may provide important new insights into the mechanism of high-Tc superconductivity. These studies also hold the promise of opening new paths for the science and technology of these novel materials, and for other materials where strongly interacting electrons dominate the physics. This project also involves the training of undergraduate students, graduate students and postdoctoral scientists in materials physics, a field of great technological importance.