Disorder and Correlations in Novel Low Dimensional Systems

新型低维系统中的无序性和相关性

• 批准号: 9972151
• 负责人: Philip Adams
• 金额: $ 28.5万
• 依托单位: Louisiana State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-01 至 2002-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9972151&HistoricalAwards=false
• 关键词: Disorder; Correlations; Novel; Low; Dimensional

9972151AdamsThe project investigates the electronic properties of ultra-thin, low atomic mass, metal films and wires. This work is of interest to a widespread condensed matter community studying the roles of disorder, correlations, and dimensionality in quantum transport phenomena. The project is focused on two areas. The first is parallel magnetic field studies of thin film superconductors where coupling of the magnetic field to the electronic spins drives the system into the normal state via a first-order phase transition. Associated with this transition are some novel and as of yet poorly understood non-equilibrium behavior such as avalanches, state memory and reentrance. The goal of this part of the project is to more fully investigate the roles of disorder and dimensionality on the non-equilibrium behavior and to look for possible applications of the state memory effect. The second area of study involves magneto-transport and density of states measurements of very high resistance metal films. The ultimate goal is to make the first measurements of the Coulomb gap (Efros-Shklovskii gap) in a 2D system and then correlate the gap behavior with the observed magneto-transport behavior in the insulating phase. Ultra-thin, homogeneously disordered Be films will be used for these studies. These projects afford excellent opportunities for training of undergraduate students, graduate students, and post-docs. This research, in fact, bridges a gap between esoteric quantum physics and more technologically oriented material science.%%%This research project investigates the electronic properties of ultra-thin, low atomic mass, metal films and wires in extreme environments. Since the project involves both the fabrication of samples and measurements on those samples, it offers unusually broad educational and research opportunities for students and post-docs. Two projects will be pursued: One involves the behavior of thin film superconductivity in very high parallel (to the film surface) magnetic fields. This transition is fundamentally quantum in nature and displays unusual quasi-static non-equilibrium behavior such as avalanches and memory effects. The microscopic origin of these effects is still not understood but is expected to impact the general field of quantum phase transitions. The other concerns the role of electron-electron interactions in the electron transport properties of very high resistance Be films. It is believed that the non-granular character of the Be films will allow progress to be made on this very important problem that is now known to be relevant to a wide variety of condensed matter problems.***

9972151亚当斯该项目研究超薄，低原子质量，金属薄膜和电线的电子特性。 这项工作是感兴趣的一个广泛的凝聚态社区研究的作用，无序，相关性和维度的量子输运现象。 该项目侧重于两个领域。第一个是薄膜超导体的平行磁场研究，其中磁场与电子自旋的耦合通过一阶相变驱动系统进入正常状态。 与这种转变相关的是一些新的，但知之甚少的非平衡行为，如雪崩，状态记忆和再入。 这一部分的目的是更全面地研究无序和维度对非平衡行为的作用，并寻找状态记忆效应的可能应用。 研究的第二个领域涉及非常高的电阻金属膜的磁输运和状态密度测量。 最终目标是在二维系统中首次测量库仑能隙（Efros-Shklovskii能隙），然后将差距行为与观察到的绝缘相中的磁输运行为相关联。 超薄，均匀无序的Be膜将用于这些研究。 这些项目为培养本科生、研究生和博士后提供了极好的机会。 事实上，这项研究在深奥的量子物理学和更技术化的材料科学之间架起了一座桥梁。该研究项目旨在研究极端环境下超薄、低原子质量金属薄膜和导线的电子特性。 由于该项目涉及样品的制造和对这些样品的测量，它为学生和博士后提供了非常广泛的教育和研究机会。两个项目将进行：一个涉及的行为薄膜超导在非常高的平行（薄膜表面）磁场。这种转变本质上是量子的，并显示出不寻常的准静态非平衡行为，如雪崩和记忆效应。 这些效应的微观起源仍然不清楚，但预计会影响量子相变的一般领域。另一个问题是电子-电子相互作用在高阻Be膜的电子输运性质中的作用。据信，Be薄膜的非颗粒特性将使这个非常重要的问题取得进展，现在已知这个问题与各种各样的凝聚态问题有关。