Imaging the Gauge-Invariant Phase Difference of Superconductors

非技术：这个项目将建造一种新型的扫描隧道显微镜，并用它在原子尺度上研究超导体，温度比绝对零度高出零点几度。该显微镜包括一个尖锐的尖端，它可以在被研究的表面上以受控的方式移动，以及相关的电子设备，用于测量尖端和表面之间流动的电流。当尖端在表面上移动时，这种电流(隧道电流)的变化表明该表面的性质发生了变化。该项目的目标不仅是开发一种新型的成像技术，而且要深入了解产生高温超导的未知机制。对这一机制的了解可能会导致新的超导体的转变温度高到足以对技术产生重大影响。其他广泛的影响包括在具有持续科学和技术重要性的领域培训研究生和博士后，这些领域包括低温物理、原子尺度的显微镜、材料物理和超导。该项目将致力于增加妇女和少数民族对物理学的参与，改善物理学本科生和研究生教育，并促进与拉丁美洲和东欧科学家的合作。技术：该项目将建造一种新型的低温扫描隧道显微镜(STM)，并用它在原子尺度上测量超导体相位差的空间变化。该显微镜由一个与真空隧道结并联的约瑟夫森结组成，真空隧道结形成在超导STM针尖和所研究的超导体表面之间。为了最大限度地减少热噪声的影响，整个系统将在稀释制冷机中冷却到0.1K以下。在对众所周知的超导材料进行测试后，该系统将被用于研究原子缺陷、台阶、晶界和其他表面不规则性附近的局域位相差的空间变化，最终探索导致高温超导体超导电性的未知机制。该项目将支持在低温物理、扫描近场显微镜、材料物理和超导器件等具有持续科学和技术意义的领域对研究生和博士后进行培训。该项目将致力于增加妇女和少数民族对物理学的参与，改善物理学本科生和研究生教育，并促进与拉丁美洲和东欧科学家的合作。

Non-Technical:This project will construct a novel type of scanning tunneling microscope and use it to study superconductors at the atomic scale at temperatures that are a small fraction of a degree above absolute zero. The microscope includes a sharply pointed tip, which can be moved in a controlled manner across a surface under study, and the associated electronics for measuring the electric current that flows between the tip and the surface. Changes in this current (the tunneling current) as the tip is moved over the surface indicate variations in the properties of this surface. The goal of the project is not only to develop a new type of imaging but also to obtain insight into the as yet unknown mechanism that is producing high-temperature superconductivity. Knowledge of this mechanism could lead to new superconductors with transition temperatures that are high enough to have a significant impact on technology. Other broad impacts include training of graduate students and postdoctoral students in areas of continuing scientific and technological importance, including low-temperature physics, microscopy at the atomic scale, materials physics, and superconductivity. The project will work to increase the participation of women and minorities in the physical sciences, improve undergraduate and graduate education in physics, and foster collaborations with scientists from Latin America and Eastern Europe.Technical:This project will build a novel type of low temperature scanning tunneling microscope (STM) and use it to measure spatial variations in the phase difference of superconductors at the atomic scale. This microscope consists of a Josephson junction connected in parallel with a vacuum tunnel junction, which is formed between the superconducting STM tip and the surface of the superconductor under study. To minimize the impact of thermally generated noise, the entire system will be cooled in a dilution refrigerator to below 0.1 K. After testing on a well-understood superconducting material, the system will be used to examine spatial variations in the local phase difference near atomic defects, steps, grain boundaries and other surface irregularities and ultimately to probe the unknown mechanism causing superconductivity in the high-transition temperature (Tc) superconductors. The project will support the training of graduate students and postdoctoral students in areas of continuing scientific and technological significance, including low-temperature physics, scanning near-field microscopy, materials physics and superconducting devices. The project will work to increase the participation of women and minorities in the physical sciences, improve undergraduate and graduate education in physics, and foster collaborations with scientists from Latin America and Eastern Europe.