A Novel Gap Spectroscopy Tool and Discovery of New Nodal Superconductors

新型间隙光谱工具和新型节点超导体的发现

• 批准号: 1410712
• 负责人: Steven Anlage
• 金额: $ 35.9万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-15 至 2018-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1410712&HistoricalAwards=false
• 关键词: Novel; Gap; Spectroscopy; Tool; Discovery

Non-Technical AbstractBecause of their high transition temperatures and exotic new correlated electronic states, high temperature superconductors show a great potential for transformative applications, such as quantum information processing. The objective of this project is to discover new classes of unconventional superconducting materials and to examine them for evidence of unconventional superconductivity using a new experimental technique that the principal investigator discovered. The project trains graduate students with backgrounds in physics and engineering to discover new materials and phenomena at the forefront of condensed matter physics research. The students also participate in international research, carrying out part of their Ph.D. research at the Center for Functional Nanostructures at the Karlsruhe Institute of Technology in Germany. The US and German laboratories complement each other, thus enhancing the educational experience for the graduate students involved. The principal Investigator has a history of broadening the participation of underrepresented groups and is involved in outreach activities to recruit more underrepresented students. This project is establishing a new experimental technique of interest to condensed matter researchers, creating new partnerships, collaborations, and facilities that impact the landscape of the superconducting materials and applications fields. Technical AbstractThis award from the Condensed Matter Physics Program in the Division of Materials Research supports the University of Maryland with a project focused on the quest to discover new superconducting materials with new properties, and to further refine the anisotropic nonlinear Meissner effect spectroscopy method into a broadly useful technique that contributes significant results to the ongoing debates about the pairing mechanism in unconventional superconductors. The principal investigator's discovery of the anisotropic nonlinear Meissner effect photoresponse helps to speed up the discovery of superconducting materials with nontrivial and exotic properties. The method relies on the anisotropic nonlinear Meissner effect, and the presence of Andreev bound states, to create images of the nonlinear electrodynamic response of the superconductor that illustrate the superconducting gap nodal directions. The method is sensitive to both bulk properties (through the superfluid anisotropic nonlinear response) and surface properties (through measurement of Andreev bound states associated with the unconventional order parameter). A superconducting thin film is patterned into a compact self-resonant spiral structure, excited near resonance in the radio-frequency range, and scanned with a focused laser beam perturbation. At low temperatures, direction-dependent nonlinearities in the reactive and resistive properties of the resonator create photoresponse that maps out the directions of nodes, or of bound states associated with these nodes, on the Fermi surface of the superconductor. The method was demonstrated on a known nodal superconductor, so the next step is to discover new nodal superconductors by extending the method to work on single crystals and un-patterned thin films. The co-PI grows the new superconducting materials and the PI performs the experiments both in-house and in collaboration with a group in Karlsruhe, Germany, to discover new nodal superconductors. The new materials discovered should have potential for transformative applications, including new forms of superconducting electronics, or sensitive single-photon detectors. The results are disseminated through publications, talks and posters at international conferences, a research web site, a tutorial web site explaining how to set up a nonlinear Meissner effect experiment with minimal equipment, and continuation of the outreach activities by the PI, co-PI and students.

由于高温超导体的高转变温度和奇异的新的相关电子态，高温超导体显示出巨大的应用潜力，如量子信息处理。 该项目的目标是发现新的非常规超导材料类别，并使用首席研究员发现的新实验技术来检查它们以寻找非常规超导性的证据。 该项目培养具有物理和工程背景的研究生，以发现凝聚态物理研究前沿的新材料和现象。 学生们还参加国际研究，开展他们的博士学位的一部分。这是德国卡尔斯鲁厄理工学院功能纳米结构中心的一项研究。 美国和德国的实验室相互补充，从而增强了相关研究生的教育经验。 首席研究员有扩大代表性不足群体参与的历史，并参与外联活动，以招募更多代表性不足的学生。 该项目正在建立凝聚态研究人员感兴趣的新实验技术，创造新的伙伴关系，合作和设施，影响超导材料和应用领域的前景。 技术摘要该奖项来自材料研究部凝聚态物理计划，支持马里兰州大学的一个项目，该项目致力于探索具有新特性的新超导材料，并进一步将各向异性非线性迈斯纳效应光谱学方法改进为一种广泛有用的技术，为正在进行的关于非常规超导体中配对机制的辩论提供重要结果。 主要研究者对各向异性非线性迈斯纳效应光响应的发现有助于加快发现具有非平凡和奇异性质的超导材料。 该方法依赖于各向异性的非线性迈斯纳效应，和Andreev束缚态的存在下，创建图像的非线性电动力学响应的超导体，说明超导间隙节点方向。 该方法是敏感的体属性（通过超流各向异性非线性响应）和表面性质（通过测量Andreev束缚态与非常规序参数）。 将超导薄膜图案化为紧凑的自谐振螺旋结构，在射频范围内的谐振附近激发，并用聚焦激光束扰动扫描。 在低温下，谐振器的电抗和电阻特性中的方向依赖非线性产生光响应，该光响应在超导体的费米表面上映射出节点或与这些节点相关联的束缚态的方向。 该方法在已知的节点超导体上得到了证明，因此下一步是通过将该方法扩展到单晶和未图案化的薄膜来发现新的节点超导体。 co-PI生长新的超导材料，PI在内部和与德国卡尔斯鲁厄的一个小组合作进行实验，以发现新的节点超导体。 新材料的发现应该具有变革性应用的潜力，包括新形式的超导电子学或灵敏的单光子探测器。 研究结果通过出版物、国际会议上的讲座和海报、研究网站、解释如何用最少设备建立非线性迈斯纳效应实验的教程网站以及PI、co-PI和学生继续开展的外联活动进行传播。