Disentangling Pseudogap from Superconductivity in the Cuprates by Scanning Tunneling Microscopy

高温超导体(HTS)中电子态的性质和行为一直是人们争论的焦点。在超导转变温度以上观察到的伪隙状态，被一些人视为超导状态的前兆。其他人认为这是一个相互竞争的阶段。尽管做了大量的实验和理论工作，但这个问题仍然备受争议，也是我们总体上理解HTS的核心。这一个人研究人员奖支持使用依赖温度的扫描隧道显微镜(STM)来研究这种关系。实验将在Bi2Sr2CuO6x和YBa2Cu3O6x中进行，在Bi2Sr2CuO6x和YBa2Cu3O6x中，我们之前观察到了竞争相的证据，YBa2Cu3O6x是更常用的研究对象，但还没有用最近开发的扫描隧道显微镜技术进行研究。超高真空、变温扫描隧道显微镜是一项要求很高的实验技术；高温超导作为一大类强关联电子系统的一部分，处于许多凝聚态物理的中心。因此，这个项目将是学生们的一个极好的训练基地。此外，该奖项还将支持在令人信服的科学奥秘和高温超导技术前景的推动下向广大受众进行科学推广。*非技术摘要*超导体是一种材料，它可以在没有电阻的情况下携带电流，并通过产生热量来产生能量损失。不幸的是，这种在技术上有用的特性只有在非常低的温度下才会启动，低于“转变温度”。二十多年前，一种新的“高温超导体”被发现，其转变温度接近100K。与室温(300K)相比，这仍然是非常冷的，但导致了密集的技术，如能源基础设施和科学发展。这一个人研究人员奖支持对高温超导体的实验研究，目的是了解它们在转变温度以上(在某些材料中甚至高于室温)的非常规性质与超导电性之间的关系。有人提出，这些较高的温度性质与超导电性竞争或干扰，通过了解和控制它们，转变温度可能会显著提高。在研究这一提议的同时，学生将接受广泛的实验技术培训。此外，令人信服的科学奥秘和高温超导的技术前景使科学能够接触到更广泛的受众，这也得到了该奖项的支持。

****TECHNICAL ABSTRACT****The nature and behavior of electronic states in high temperature superconductors (HTS) are the center of much debate. The pseudogap state, observed above the superconducting transition temperature, is seen by some as a precursor to the superconducting state. Others view it as a competing phase. Despite much experimental and theoretical work, this question remains highly debated and central to our understanding of HTS in general. This individual investigator award supports the investigation of this relationship by temperature dependent scanning tunneling microscopy (STM). Experiments will be performed in both Bi2Sr2CuO6+x, in which we have previously observed evidence for a competing phase, and YBa2Cu3O6+x, which is more commonly studied but has not been investigated with recently developed STM techniques. Ultrahigh vacuum, variable temperature scanning tunneling microscopy is a demanding experimental technique; HTS, as part of the broad class of strongly correlated electron systems, are at the center of much condensed matter physics. Hence this project will be an excellent training ground for students. Furthermore, this award will support science outreach to broad audiences driven by the compelling scientific mystery and technological promise of high temperature superconductivity.****NON-TECHNICAL ABSTRACT****Superconductors are materials that can carry current without resistance and resultant energy losses through heat generation. Unfortunately, this technologically useful property only turns on at very low temperatures, below a "transition temperature." Just over twenty years ago a new class of "High Temperature Superconductors" were discovered, with transition temperatures near 100 K. This is still very cold compared to room temperature (300 K), but has led to intense technological, such as energy infrastructure, and scientific development. This individual investigator award supports the experimental investigation of high temperature superconductors with the goal of understanding the relationship between their unconventional properties above the transition temperature (even above room temperature in some materials) and superconductivity. It has been proposed that these higher temperature properties compete, or interfere, with superconductivity, and that by understanding and controlling them transition temperatures may be significantly increased. While investigating this proposal, students will be trained in a wide range of experimental techniques. Furthermore, the compelling scientific mystery and technological promise of high temperature superconductivity enables scientific outreach to broad audiences, also supported by this award.