Superconductor-Insulator Transitions of Ultra-thin Films

超薄膜的超导体-绝缘体转变

• 批准号: 1263316
• 负责人: Allen Goldman
• 金额: $ 57.5万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1263316&HistoricalAwards=false
• 关键词: Superconductor; Insulator; Transitions; Ultra; thin

****Technical Abstract****This program will investigate superconductor-insulator transitions (SITs) of ultrathin films of elements and simple compounds. These transitions are the simplest examples of continuous quantum phase transitions, which occur at zero temperature, when the ground state of a system is changed in response to the variation of an external parameter. Quantum phase transitions, which are macroscopic manifestations of quantum mechanics, are studied through measurements of behaviors influenced by quantum fluctuations that persist at low, but nonzero temperatures. Investigations will include a study of the Nernst effect across the magnetic-field-tuned transition, and measurements of the penetration depth in the critical region with the goal of identifying the critical exponent of the order parameter and the universality class. In addition, the electronic compressibility near the critical point, which would be a thermodynamic signature of the SI transition, and the dissipation-tuned-SI-transition will be investigated. Electric double layer transistor configurations will be used to modify the electronic and superconducting properties of FeSe films. The broader impacts include training of graduate students in a traditional physics Ph.D. program and providing a venue for useful and positive research experiences for undergraduates. The work proposed will impact the understanding of known novel superconductors and the search for new ones. The primary outreach activity will be the teaching of freshman seminars by the PI on physics topics. ****Non-Technical Abstract****This award supports investigations of the superconductor-insulator transitions of elements and simple compounds. Superconductor-insulator transitions are among the simplest quantum phase transitions, and they are especially fundamental because of their connection to the Uncertainty Principle of quantum mechanics. Quantum phase transitions are an important paradigm in contemporary condensed matter science and understanding their nature is an important challenge in part because of their role in high temperature superconductivity. Quantum phase transitions, in contrast with conventional thermodynamic phase transitions, which are controlled by temperature, and occur at nonzero temperature, are transitions, which are controlled by external parameters such as magnetic field, pressure, or charge density, and occur at absolute zero. They have measurable signatures at low, but nonzero temperatures, which will be used to characterize them. The study of superconductor-insulator transitions requires advanced tools of experimental science such as nanofabrication, thin film growth, and ultra-low temperature cryogenic measurement techniques. This project supports the training of both Ph.D. and undergraduate students that is excellent preparation for a scientific career. The primary outreach activity will be the teaching of freshman seminars by the PI on contemporary physics topics.

*技术摘要*这个项目将研究元素和简单化合物超薄膜的超导体-绝缘体转变(SITS)。这些相变是连续量子相变的最简单的例子，当系统的基态随着外部参数的变化而改变时，在零温度下发生。量子相变是量子力学的宏观表现，通过测量在低温但非零温度下持续存在的量子涨落影响的行为来研究量子相变。研究将包括对磁场调谐跃迁的能斯特效应的研究，以及对临界区穿透深度的测量，目的是确定有序参数和普适类的临界指数。此外，还将研究临界点附近的电子可压缩性，这将是SI相变的热力学特征，以及耗散调谐SI相变。电双层晶体管结构将被用来改变FeSe薄膜的电子和超导性能。更广泛的影响包括培养传统物理学博士项目的研究生，并为本科生提供一个有益和积极的研究经历的场所。提出的工作将影响对已知新型超导体的理解和寻找新的超导体。主要的外展活动将是由国际物理协会教授新生关于物理专题的研讨会。*非技术摘要*本奖项支持对元素和简单化合物的超导体-绝缘体转变的研究。超导体-绝缘体转变是最简单的量子相变之一，因为它们与量子力学的测不准原理有关，所以特别重要。量子相变是当代凝聚态科学中的一个重要范式，理解它们的性质是一个重要的挑战，部分原因是它们在高温超导中所起的作用。与传统的热力学相变不同，量子相变是由温度控制的、在非零温度发生的相变，是由磁场、压力或电荷密度等外部参数控制的、在绝对零度发生的相变。它们在低温但非零温度下具有可测量的特征，这将被用来描述它们的特征。超导体-绝缘体转变的研究需要先进的实验科学手段，如纳米加工、薄膜生长和超低温测量技术。该项目支持博士和本科生的培训，这是为科学生涯做好准备的。主要的外展活动将是由国际物理协会就当代物理专题教授新生研讨会。

项目成果

Vortex variable range hopping in a conventional superconducting film

传统超导薄膜中的涡旋可变范围跳跃

• DOI: 10.1103/physrevb.96.224511
• 发表时间: 2017
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Percher, Ilana M.;Volotsenko, Irina;Frydman, Aviad;Shklovskii, Boris I.;Goldman, Allen M.
• 通讯作者: Goldman, Allen M.