Experimental Studies of Metal-Insulator Transitions and Superconductivity

9510246 Chaikin超导阵列在甚强磁场、各向异性超导体以及普通金属和两种 将研究三维异质结构。这些研究的最终目的是测试在不同的可控势中是否存在扩展的、定域的和公度的态，对这些态进行成像，并研究它们的动力学。设计成与穿透通量晶格相互作用的超导线网络将使用平版印刷技术制造。 本工作将集中在各向异性的影响，其中惊人的理论预测已作出了局域化，各向异性公度性，和温度相关的通量晶格配置。约瑟夫森的钉扎和动力学 涡流 块状超导体 将 被 进一步调查。 用高纯度有机超导体对磁场诱导电子一维化的激发理论预测和在高磁场下超导性的重建也将进行实验测试。 在另一个实验中，基于嵌段共聚物自组装的新型光刻技术将用于制造“纳米”周期性 电位 (~ 300奥 间距） 对 正常 金属、超导体和量子霍尔器件。这将允许研究一个新的机制，其中周期性势是可比的磁长度，并远远短于许多特征移相和散射长度。 %超导阵列中的极强磁场、各向异性超导体以及普通金属和两种 将研究三维异质结构。具体地说，本研究将解决如何将已被充分理解的周期势推广到存在竞争长度尺度和不同类型的各向异性的准周期势的问题。 设计成与穿透通量晶格相互作用的超导线网络将使用平版印刷技术制造。这项工作将集中于各向异性的影响， 关于 本地化， 向异性 可公度性， 和温度相关的磁通点阵结构。 超导体中约瑟夫森涡的钉扎和动力学将得到进一步的研究。 用高纯度有机超导体对磁场诱导电子一维化的激发理论预测和在高磁场下超导性的重建也将进行实验测试。 在另一个实验中，基于嵌段共聚物自组装的新型光刻技术将被用于在普通金属、超导体和量子霍尔器件上制造“纳米”周期性电势。 这将允许研究一个新的机制，其中周期性的势是可比的磁长度，并远远短于许多特征长度。 ***

9510246 Chaikin Superconducting arrays in very high magnetic field, anisotropic superconductors, as well as normal metals and two dimensional heterostuctures will be studied. The ultimate goal of these studies is to test for the existence of extended, localized and commensurate states in different controllable potentials, to image these states, and to study their dynamics. Superconducting wire networks designed to interact with a penetrating flux lattice will be fabricated using lithographic techniques. This work will focus on the effect of anisotropy where striking theoretical predictions have been made, about localization, anisotropic commensurability, and temperature dependent flux lattice configurations. The pinning and dynamics of Josephson vortices in bulk superconductors will be further investigated. The exciting theoretical prediction of magnetic field induced one dimensionalization of the electrons and the resulting re- establishment of superconductivity at high magnetic field will also be experimentally tested using high purity organic superconductors. In another experiment, novel lithographic techniques based on self assembly of block copolymers, will be used to fabricate "nano" periodic potentials (~ 300Ao spacing) on normal metals, superconductors and quantum Hall devices. This will allow the study of a new regime where the periodic potential is comparable to magnetic lengths and much shorter than many characteristic dephasing and scattering length. %%% Superconducting arrays in very high magnetic field, anisotropic superconductors, as well as normal metals and two dimensional heterostuctures will be studied. Specifically this research will address the question of how the well understood periodic potentials can be extended to quasi-periodic potentials where there are competing length scales and different types of anisot ropy. Superconducting wire networks designed to interact with a penetrating flux lattice will be fabricated using lithographic techniques. This work will focus on the effect of anisotropy where striking theoretical predictions have been made, about localization, anisotropic commensurability, and temperature dependent flux lattice configurations. The pinning and dynamics of Josephson vortices in bulk superconductors will be further investigated. The exciting theoretical prediction of magnetic field induced one dimensionalization of the electrons and the resulting re- establishment of superconductivity at high magnetic field will also be experimentally tested using high purity organic superconductors. In another experiment, novel lithographic techniques based on self assembly of block copolymers, will be used to fabricate "nano" periodic potentials on normal metals, superconductors and quantum Hall devices. This will allow the study of a new regime where the periodic potential is comparable to magnetic lengths and much shorter than many characteristic lengths. ***