Measurement of the Superfluid Density and other Electronic Properties of Electron-Doped Cuprate Superconductors

电子掺杂铜酸盐超导体的超流体密度和其他电子特性的测量

• 批准号: 0203739
• 负责人: Thomas Lemberger
• 金额: --
• 依托单位: Ohio State University Research Foundation -DO NOT USE
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-06-01 至 2006-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0203739&HistoricalAwards=false
• 关键词: Measurement; Superfluid; Density; other; Electronic

This project focuses on electronic properties of CuO(2) planes in electron-doped cuprates, e.g., Pr(2-x)Ce(x)CuO(4) and La(2-x)Ce(x)CuO(4), in comparison with hole-doped cuprates, especially the closely-related compound La(2-x)Sr(x)CuO(4). At issue is the nature of the superconducting state in e-doped cuprates, and whether there is a transition in pairing symmetry near optimal doping. The project will provide the first measurements of two quantities of fundamental importance. One is the magnitude and temperature dependence of the superfluid density, which is proportional to the inverse square of the magnetic penetration depth. The penetration depth will be measured from 0.5 K up to the superconducting transition temperature in samples spanning a wide doping range, x. Another is the electronic heat capacity anomaly at the superconducting transition. Supporting measurements of normal-state transport, e.g., resistivity and Hall coefficient will also be made. Research will provide excellent training in state-of-the-art experimental techniques to graduate and undergraduate students. This project benefits from a collaboration with the world's premier maker of electron doped cuprate films, Dr. Michio Naito of NTT, Japan.A central issue in condensed matter physics and in materials science is identification of microscopic mechanisms that enable electrons to move within a solid, rather than being attached to a particular atom. The present project focuses on understanding electrons that move within copper-oxide planes in a class of superconducting compounds that includes Pr(2-x)Ce(x)CuO(4) and La(2-x)Ce(x)CuO(4). Superconductivity in these copper-oxide compounds has been the subject of intense international research efforts since their discovery in 1986. The main question now is whether the superconducting state in these compounds is the same as found in a very similar compound, La(2-x)Sr(x)CuO(4). To illuminate this issue, the project will provide measurements of the magnitudes and temperature dependencies of quantities of fundamental importance, namely, the density of superconducting electrons, and the contribution of superconducting electrons to the heat capacity at the transition into the superconducting state. The research will provide excellent training in state-of-the-art experimental techniques to graduate and undergraduate students.

本项目的重点是电子掺杂铜酸盐中CuO（2）平面的电子性质，例如，Pr（2-x）Ce（x）CuO（4）和La（2-x）Ce（x）CuO（4），并与空穴掺杂的铜酸盐，特别是与空穴掺杂密切相关的化合物La（2-x）Sr（x）CuO（4）进行了比较。争论的焦点是掺e铜氧化物超导态的性质，以及在最佳掺杂附近是否存在对对称性的转变。该项目将首次测量两个具有根本重要性的量。一个是超流密度的大小和温度依赖性，这是成正比的磁穿透深度的平方反比。 穿透深度将从0.5 K测量到样品的超导转变温度，跨越宽的掺杂范围，x。 另一个是超导转变时的电子热容反常。 支持正常状态传输的测量，例如，电阻率和霍尔系数也将被测量。 研究将为研究生和本科生提供最先进的实验技术方面的优秀培训。 该项目得益于与世界领先的电子掺杂铜酸盐薄膜制造商日本NTT的Michio Naito博士的合作。凝聚态物理学和材料科学的一个核心问题是确定使电子能够在固体中移动的微观机制，而不是附着在特定的原子上。本项目的重点是了解电子在一类超导化合物中的氧化铜平面内移动，包括Pr（2-x）Ce（x）CuO（4）和La（2-x）Ce（x）CuO（4）。自1986年发现这些氧化铜化合物以来，它们的超导性一直是国际研究工作的主题。现在的主要问题是，这些化合物的超导态是否与在一种非常相似的化合物La（2-x）Sr（x）CuO（4）中发现的超导态相同。为了阐明这个问题，该项目将提供对具有根本重要性的量的幅度和温度依赖性的测量，即超导电子的密度以及超导电子对转变为超导态时热容量的贡献。这项研究将为研究生和本科生提供最先进的实验技术方面的优秀培训。