Topological Hysteresis, Structure and Nucleation of the Intermediate State in Type-I Superconductors

摘要超导中间态是在元素超导体（ⅰ型）中形成的，是正常区和超导区的复合模式。新开发的实验技术可能会导致我们目前对这种状态的理解的实质性修订。这些技术允许人们实时观察中间状态的局部磁场，并以极高的灵敏度进行测量。这项研究与复杂的数学、地球物理、化学和生物系统中模式形成的重要问题，甚至与星系的形成有关。该项目具有重大的教育影响。所有级别的学生都将参与该项目，每个学生执行一套特定的测量方法。一些实验将成为先进固体物理实验室的一部分。该项目涉及与该领域领先专家的积极国内和国际合作，包括几十年前发起相关研究的专家。计划在本学期末举办一次关于i型超导体模式形成的研讨会。技术摘要：该个人研究者奖将支持i型超导体中间态的综合研究。独特的实验技术，如磁场的磁光可视化和微电子动磁灵敏隧道二极管电纳测量，结合传统方法，将被用来理解在高度非线性系统中更广泛的模式形成背景下的中间状态。拓扑滞后和复杂形状效应的研究可能导致不寻常的热力学平衡状态的识别，并最终对我们目前对型等超导的理解进行实质性的修订。利用温度和磁场连续调谐系统的能力使i型超导成为研究非线性系统中模式形成的一般问题的理想场所。作为该项目的一部分，将研究与生物、化学和天体物理系统的联系。该项目具有重大的教育影响。所有级别的学生都将参与该项目，每个学生执行一套特定的测量方法。一些实验将成为高级固体物理实验室的一部分。该项目涉及与该领域领先专家的积极国内和国际合作，包括几十年前发起相关研究的专家。计划在本学期末举办一次关于i型超导体模式形成的研讨会。

Non-technical abstractThe superconducting intermediate state is formed in elemental (type-I) superconductors as acomplex pattern of normal and superconducting regions. Newly developedexperimental techniques may lead to a substantial revision of our currentunderstanding of this state. These techniques allow one to observe localmagnetic fields of the intermediate state in real time and to measure themwith extreemly high sensitivity. This research has connections to importantquestions of pattern formation in complex mathematical, geophysical,chemical and biological systems and even to the formation of galaxies. Theproject carries significant educational impact. Students of all levels willwork on the project, each performing specific set of measurements. Someexperiments will be part of the advanced solid-state physics laboratory. Theproject involves active domestic and international collaborations with theleading experts in the field, including those who initiated related studiesdecades ago. A workshop on pattern formation in type-I superconductors isplanned at the end of the research term.Technical abstractThis individual investigator award will support comprehensive studies of theintermediate state in type-I superconductors. Unique experimentaltechniques, such as magneto-optical visualization of magnetic fields andpico-emu sensitive tunnel-diode susceptometry, combined with conventionalmethods, will be employed to understand the intermediate state in a broadercontext of pattern formation in highly nonlinear systems. The study oftopological hysteresis and complex shape effects may lead to theidentification of unusual thermodynamically equilibrium states and,ultimately, to substantial revisions of our current understanding of type-Isuperconductivity. The ability to continuously tune the system across abroad range of topologies using both temperature and magnetic field makestype-I superconductivity an ideal arena in which to study general questionsof pattern formation in nonlinear systems. Connections to biological,chemical and astrophysical systems will be studied as part of this project.The project carries significant educational impact. Students of all levelswill work on the project, each performing specific set of measurements. Someexperiments will be part of the advanced solid-state physics lab. Theproject involves active domestic and international collaborations with theleading experts in the field, including those who initiated related studiesdecades ago. A workshop on pattern formation in type-I superconductors isplanned at the end of the research term.