Localization and Critical Phenomena in Disordered Media

无序媒体中的定位和关键现象

• 批准号: 9107752
• 负责人: Michael Stephen
• 金额: $ 24万
• 依托单位: Rutgers University New Brunswick
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-07-15 至 1995-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9107752&HistoricalAwards=false
• 关键词: Localization; Critical; Phenomena; Disordered; Media

Research will be conducted on properties of flux lines in superconductors and on localization, multiple scattering and interference of waves in disordered media. For the first topic, investigations will be undertaken on the nature of the quasiparticle excitations in the mixed state of a type II superconductor with a view to determining whether de Haas van Alphen oscillations can be observed and thus provide information on the Fermi surface of high temperature superconductors. Research will also be undertaken on the properties of disordered flux line arrays near the upper critical field using an appropriate variational order parameter. The properties of flux lines in thin films with applied field parallel to the surface will also be studied with the objective of understanding recent vibrating reed experiments. For the second topic, localization of light, the scattering of light by a disordered medium will be studied when the scattering is predominately small angle scattering. This approach leads to some interesting simplifications. The behavior appears to be dominated by interference effects. Understanding and calculating these effects is one objective of the proposed research. %%% The research conducted on this grant focusses on two areas of current interest in condensed matter and materials physics. In the first area, the fundamental properties of magnetic flux lines in type II superconductors, such as the recently discovered high temperature superconductors, will be studied. While the properties of flux lines and the structures which they form are of basic importance to the underlying physics of these superconductors, they are also of great importance to the production of real superconducting materials which have high current densities. The second area of research is the localization of waves by disorder. It has long been known that electrons travelling in disordered media, such as an amorphous semiconductor, can be localized due to the intrinsic disorder in the material. Of more recent interest is the discovery of the localization of electromagnetic waves (light) by disordered materials. This opens up the possibility of designing materials which treats light in the same way as semiconductors, say, deal with electrons. Basic research in this area can have a large impact on the design and use of photonic materials.

将对磁通线的性质进行研究， 超导体和本地化，多重散射和 波在无序介质中的干涉。 对于第一个主题， 将对该事件的性质进行调查。 第二类混合态的准粒子激发 超导体，以确定是否德哈斯货车 可以观察到Alphen振荡，从而提供以下信息： 高温超导体的费米面 研究 对无序磁通线的性质也进行了研究 在上临界场附近使用适当的 变分序参量 薄介质中磁通线的性质 具有平行于表面的施加场的膜也将 研究的目的是了解最近的振动簧片 实验 对于第二个主题，光的局部化， 光散射的无序介质将被研究时， 散射主要是小角度散射。 这种方法 导致了一些有趣的简化。 这种行为似乎 受干扰效应支配。 理解和 计算这些影响是所提出的目标之一， research. %%% 利用该补助金进行的研究集中在两个领域， 目前对凝聚态和材料物理感兴趣。 在 第一个领域，磁通线的基本性质， 第二类超导体，如最近发现的高 高温超导体，将被研究。 虽然属性 磁通线和它们所形成的结构是基本的 重要性的基础物理这些超导体，他们 对生产真实的 具有高电流密度的超导材料。 的 第二个研究领域是通过无序来定位波。 人们早就知道，电子以无序的方式运动， 诸如非晶半导体之类的介质可以由于 材料的内在无序。 最近的兴趣是 电磁波（光）局部化的发现 无序的材料。 这开启了 设计材料，以同样的方式对待光， 比如说，半导体处理电子。 基础研究在此 面积可以对光子器件的设计和使用产生很大的影响， 材料.