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

非技术摘要超导中间态是在元素(第一类)超导体中形成的由正常区域和超导区组成的复杂模式。新发展的实验技术可能会对我们目前对这一状态的理解进行实质性的修订。这些技术使人们能够实时观察中间态的局域磁场，并以极高的灵敏度测量它们。这项研究与复杂的数学、地球物理、化学和生物系统中的图案形成的重要问题有关，甚至与星系的形成有关。该项目具有重大的教育影响。所有级别的学生都会参与这个项目，每个人都会执行一套特定的测量方法。一些实验将成为先进的固体物理实验室的一部分。该项目涉及与该领域的领先专家进行积极的国内和国际合作，包括那些几十年前开始相关研究的专家。计划在研究期末举办一次关于第一类超导体中图案形成的研讨会。技术摘要这一个人研究人员奖将支持对第一类超导体中间态的全面研究。独特的实验技术，如磁场的磁光可视化和微微磁光敏感的隧道二极管灵敏度测量，与传统方法相结合，将被用来在更广泛的高度非线性系统的图案形成的背景下理解中间态。对拓扑滞后和复杂形状效应的研究可能导致对不寻常的热力学平衡态的识别，并最终对我们目前对I型超导的理解进行实质性的修正。利用温度和磁场在各种拓扑结构中连续调节系统的能力使I型超导成为研究非线性系统中图案形成的一般问题的理想场所。作为该项目的一部分，将研究生物、化学和天体物理系统之间的联系。该项目具有重大的教育影响。所有级别的学生都将参与这个项目，每个学生都要进行一系列特定的测量。一些实验将成为高级固态物理实验室的一部分。该项目涉及与该领域的领先专家进行积极的国内和国际合作，包括那些几十年前开始相关研究的专家。计划在研究期末举办一次关于第一类超导体中图案形成的研讨会。

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.