Experimental Investigation of Competing Orders, Quantum Criticality and Spin/Charge Transport in Cuprate Superconductors

铜酸盐超导体中竞争级数、量子临界性和自旋/电荷输运的实验研究

• 批准号: 0103045
• 负责人: Nai-Chang Yeh
• 金额: $ 31.5万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-15 至 2004-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0103045&HistoricalAwards=false
• 关键词: Experimental; Investigation; Competing; Orders; Quantum

This individual investigator award is for an experimental research project that will address some of the most fundamental physics issues associated with high-temperature superconducting cuprates. The primary objectives are: [1] To investigate the competing orders and possible existence of a quantum critical point in different families of hole-doped (p-type) cuprate superconductors as a function of the doping level and temperature by means of low-temperature scanning tunneling microscopy (STM) and spectroscopy (STS). [2] To compare the pairing potential, pairing symmetry, and competing orders in the electron-doped (n-type) cuprate superconductors with those in the p-type cuprates. [3] To elucidate the characteristics of spin and charge transport in the p-type cuprate superconductors by studying the effects of spin-polarized and simple quasiparticle injection in perovskite ferromagnet-insulator-superconductor (F-I-S) and in normal metal-insulator-superconductor (N-I-S) heterostructures. The superior spatial resolution of STM/STS is expected to provide unique information for the microscopic properties of cuprate superconductors, and the investigation of spin/charge transport in these superconductors can yield insights into the roles of spin- and charge-degrees of freedom in their pairing state. In addition to the potentially significant impact of these studies on revealing the fundamental physics of cuprate superconductivity, the wide range of forefront experimental techniques employed in conducting this project will provide sound technical and scientific training for the participating students and postdoctoral researchers. Furthermore, novel microelectronic devices based on the tunable superconducting properties of F-I-S heterostructures under variable spin-polarized quasiparticle currents may be devised for a range of applications.%%%This individual investigator award will fund an experimental research project that attempts to address some of the most fundamental physics issues and potential applications associated with high-temperature superconducting cuprates. There are two primary experimental approaches. One involves the use a low-temperature scanning tunneling microscope (STM) to study the microscopic physical properties of cuprates with atomic-scale spatial resolution, thereby proving direct information for the quantum nature of these unconventional superconductors. The other experimental approach involves studying how various superconducting properties of the cuprates are modified under the injection of electrical currents in novel devices comprising of thin-film layers of ferromagnet-insulator-superconductor (F-I-S) and normal metal-insulator-superconductor (N-I-S) heterostructures. In addition to potentially significant impact of these studies on revealing the fundamental physics of cuprate superconductivity, the wide range of frontier experimental techniques employed in conducting this project will provide sound technical and scientific training for the participating students and postdoctoral researchers. Furthermore, the tunable superconducting properties of the F-I-S heterostructures under variable injection currents are promising candidates for various microelectronic device applications.***

这个个人研究者奖是一个实验研究项目，将解决一些最基本的物理问题与高温超导铜酸盐。主要目标是：[1]通过低温扫描隧道显微镜（STM）和光谱学（STS）研究不同系列的空穴掺杂（p型）铜酸盐超导体中的竞争顺序和量子临界点的可能存在，作为掺杂水平和温度的函数。[2]比较电子掺杂（n型）铜氧化物超导体与p型铜氧化物超导体的对势、对对称性和竞争序。[3]通过研究自旋极化和简单准粒子注入对钙钛矿铁磁-绝缘体-超导体（F-I-S）和正常金属-绝缘体-超导体（N-I-S）异质结构的影响，阐明p型铜氧化物超导体中自旋和电荷输运的特性。STM/STS的上级空间分辨率有望为铜氧化物超导体的微观性质提供独特的信息，并且这些超导体中自旋/电荷输运的研究可以深入了解自旋和电荷自由度在其配对状态中的作用。 除了这些研究对揭示铜氧化物超导性的基础物理学的潜在重大影响外，在进行该项目时采用的广泛的前沿实验技术将为参与的学生和博士后研究人员提供良好的技术和科学培训。 此外，基于F-I-S异质结构在可变自旋极化准粒子电流下的可调谐超导特性的新型微电子器件可以被设计用于一系列应用。这个个人研究者奖将资助一个实验研究项目，试图解决一些最基本的物理问题和与高温超导铜酸盐相关的潜在应用。有两种主要的实验方法。其中一个涉及使用低温扫描隧道显微镜（STM）以原子尺度的空间分辨率研究铜酸盐的微观物理性质，从而为这些非常规超导体的量子性质提供直接信息。另一种实验方法涉及研究铜酸盐的各种超导性质如何在新器件中注入电流进行修改，该器件由铁磁-绝缘体-超导体（F-I-S）和正常金属-绝缘体-超导体（N-I-S）异质结构的薄膜层组成。除了这些研究对揭示铜氧化物超导性的基础物理学具有潜在的重大影响外，开展该项目所采用的广泛的前沿实验技术将为参与的学生和博士后研究人员提供良好的技术和科学培训。 此外，F-I-S异质结构在可变注入电流下的可调超导特性是各种微电子器件应用的有希望的候选者。