A Novel Anisotropic Percolative Conductivity Transition in Thin Film Oxide Heterostructures

技术支持：该项目旨在更好地理解导电和绝缘钙钛矿氧化物薄膜异质结构的外延生长和导电机制中的基本材料科学问题，这些薄膜异质结构表现出可通过膜厚度，电压和成分调节的各向异性双折射电导率转变。该转变被认为类似于金属-绝缘体转变，但另外是长度依赖的，涉及由电压偏置触发的电子定位。该方法包括在各种条件下（薄膜厚度，电池尺寸，成分，电极类型）作为温度和场（电磁）的函数的传输测量，以及材料组合（电极，基质：导体，衬底）中的材料科学合成和处理问题，并比较材料组合的行为。此外，电子传输的量子力学建模沿着离散元件组成的接触和导电岛将进行考虑到自能量，状态占用（费米-狄拉克）统计和静电（解决等效电路基本电容器），和电荷捕获的影响。非技术性：该项目涉及电子/光子材料科学领域的基础研究问题，具有高度的技术相关性。它被认为是一个高风险/高潜力的回报项目。研究的跨学科性质以及实验和建模相结合的方法为学生提供了更多的机会，以扩大他们的教育经验。

Technical: This project aims for greater understanding of fundamental materials science issues in epitaxial growth and conduction mechanisms of thin-film heterostructures of conducting and insulating perovskite oxides that exhibit an anisotropic percolative conductivity transition tunable by film thickness, voltage and composition. The transition is thought to be similar to a metal-insulator transition but is additionally length dependent, involving electron localization triggered by a voltage bias. The approach includes transport measurements as a function of temperature and field (electrical and magnetic) under various conditions (film thickness, cell size, composition, electrode types) and material science synthesis and processing issues in materials combinations (electrodes, matrix:conductor, substrate) and to compare behaviors of materials combinations. Also, quantum mechanical modeling of electron transport along discrete elements consisting of contacts and conducting islands will be performed taking into account self energy, state occupancy (Fermi-Dirac) statistics and electrostatics (solving equivalent circuits made of essentially capacitors), and effects of charge trapping. Non-technical: The project addresses basic research issues in a topical area of electronic/photonic materials science with high technological relevance. It is considered a high risk/high potential pay-off project. The interdisciplinary nature of the research and the combined experiment and modeling approach provide additional opportunities for students to broaden their educational experience.