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****该程序将研究元素和简单化合物的超薄膜的超导体 - 绝缘体过渡（坐）。这些过渡是连续量子相变的最简单示例，当系统的基底状态因外部参数的变化而改变时，该跃迁发生在零温度下。量子相变是量子力学的宏观表现，是通过测量受量子波动影响的行为来研究的，量子波动持续低但非零温度。 研究将包括对整个磁场调节过渡的NernST效应的研究，以及对关键区域的穿透深度的测量，目的是确定顺序参数的关键指数和通用性类别。 此外，将研究临界点附近的电子可压缩性，这将是SI过渡的热力学特征，并将研究耗散调节的 - 转换。电动双层晶体管构型将用于修改FESE膜的电子和超导特性。更广泛的影响包括在传统物理博士学位上对研究生的培训。计划并为本科生提供有用和积极的研究经验的场所。提出的工作将影响对已知的新型超导体的理解，并搜索新的超导体。 主要的外展活动将是PI关于物理主题的新生研讨会的教学。 ****非技术摘要****该奖项支持对元素和简单化合物的超导体 - 绝缘体过渡的调查。超导体 - 绝缘体转变是最简单的量子相变，由于它们与量子力学的不确定性原理的联系，它们尤其是基本的。量子相变是当代凝结物质科学的重要范式，理解其性质是重要的挑战，部分原因是它们在高温超导性中的作用。 与常规热力学相变（由温度控制并在非零温度下发生的传统热力学相变相反，量子相跃迁是由磁场，压力或电荷密度等外部参数控制的，并且发生在绝对零。 它们在低的温度下具有可测量的特征，可用于表征它们。对超导体 - 绝缘体转变的研究需要实验科学的先进工具，例如纳米化，薄膜的生长和超低温度低温测量技术。该项目支持两家博士学位的培训。和本科生为科学职业做好了准备。主要的外展活动将是PI关于当代物理主题的新生研讨会的教学。

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.