Defect Dynamics and Quantum Transport in Disordered Mesoscopic Metals

摘要：为了揭示介观结构特有的新物理现象，将研究介观金属样品的低温电特性。要研究的具体问题包括无序金属中单个缺陷的耗散量子隧道效应，外加电场和应变场对微观缺陷特性的调制，以及介观超导体在增强电子量子相相干性方面的作用。大样本中1/f噪声的测量通过提供有关无序系统缺陷的统计信息来补充介观测量。非技术摘要：本提案着重于与无序金属相关的两个研究领域。第一种是对单个原子缺陷的研究。通过仔细测量亚微米样品的电导率，人们可以探测到样品中单个原子的运动。这种类型的研究揭示了个体缺陷的细节，这些细节是无法从更大样本的研究中获得的。第二个研究领域是低温下金属中电子的量子力学行为。由于它们的波状性质，金属中的电子表现出干扰。在正常和超导材料的亚微米样品中，这种干扰导致了许多新的、有趣的电学性质。这些效应可能对未来介观器件的发展产生潜在影响。＊＊＊

9321850 Birge Technical abstract: The low temperature electrical properties of mesoscopic metal samples will be studied in order to uncover new physical phenomena that are unique to the mesoscopic regime. The specific problems to be studied include dissipative quantum tunneling of single defects in disordered metals, modulation of microscopic defect properties by externally applied electric and strain fields, and the role of mesoscopic superconductors in enhancing electronic quantum phase coherence. Measurements of 1/f noise in larger samples complement the mesoscopic measurements by providing statistical information about defects in disordered systems. Non-technical abstract: This proposal focuses on two areas of study related to disordered metals. The first is the study of individual, atomic defects. By carefully measuring the electrical conductance of sub micrometer samples, one can detect the motion of a single atom within the sample. This type of study reveals details about individual defects that are not obtainable from studies of larger samples. The second area of study is the quantum-mechanical behavior of electrons in metals at low temperature. Due to their wave-like nature, electrons in metals exhibit interference. In sub micrometer samples of normal and superconducting materials, this interference leads to a number of new, intriguing electrical properties. These effects can have potential impact on the development of future mesoscopic devices. ***