ITR: Correlated Electrons in Complex Oxides and Nanoscopic Systems

该奖项支持强相关电子材料的计算和理论研究及教育。这项工作涉及算法开发、大规模计算以及将计算作为发现工具的使用。主要研究内容包括：(1)重点论证了双交换体系的现实微观材料中存在的巨磁电阻效应。PI的目的是在蒙特卡罗模拟中包括所有被认为是解释这一现象的重要成分，如Hund耦合、声子、超交换和猝灭无序。(Ii)有实验证据表明，在某些材料，特别是过渡金属氧化物的界面上发生了电子重构。这些效应表明，可以使用复合氧化物开发类似的半导体异质结构。PI将探索各种界面，包括锰酸盐-锰酸盐、超导体-锰酸盐和锰酸盐-钛酸盐。这些人工制备的体系的性质将被研究。(3)PIS将研究稀磁半导体的真实空间模型，该模型再现母体化合物的价带，考虑到随机的锰掺杂和自旋-轨道相互作用，并可用无偏见的数值技术进行研究。结果将与各种化合物的实验进行有意义的比较。(Iv)PI将使用随时间变化的密度矩阵重整化群技术来研究分子、聚合物、Mott绝缘体到金属的转变以及费米子气体的突然膨胀模型中的输运。该奖项支持研究生在凝聚态理论和材料研究方面的高级计算方法方面的培训。该研究活动涉及与拉丁美洲的研究人员的国际合作。非技术概述：该奖项支持关于复杂材料的计算和理论研究以及教育，这些材料表现出不寻常的电子性质和新的物质状态，这是电子之间强烈相互作用的结果。利用理论概念和先进的计算，PI旨在洞察物质的新状态，小磁场可能导致电流流动阻力的戏剧性变化的影响，以及电荷如何在分子中运动。他们还希望在半导体和半导体异质结构等领域发现新的磁性现象。所有这些都为未来的技术应用奠定了基础，这些应用可能会给电子学和我们对某些类别材料的理解带来革命性的变化。这一活动有助于保持美国在21世纪的竞争力，不仅是通过智力进步，也是通过教育下一代科学家，他们能够将计算作为一种发现工具，并能够在全球经济中具有竞争力。

This award supports computational and theoretical research and education on strongly correlated electron materials. The work involves algorithmic development, large scale computation, and the use of computation as a discovery tool. The main focuses of the research include:(i) Focus on demonstrating that the colossal magnetoresistance effect occurs in realistic microscopic materials of the double-exchange family. The PIs aim to include in Monte Carlo simulations all the ingredients believed to be important to explain this phenomenon, the Hund coupling, phonons, superexchange, and quenched disorder.(ii) There is experimental evidence that an electronic reconstruction occurs at the interface of certain materials, particularly the transition metal oxides. These effects suggest that analogs of semiconducting heterostructures can be developed using complex oxides. The PIs will explore a variety of interfaces including manganite-manganite, superconductor-manganite, and manganite-titanate. The properties of these artificially prepared systems will be studied. (iii) The PIs will investigate a real space model for diluted magnetic semiconductors that reproduces the valance bands of the parent compound, takes into account random manganese doping and spin-orbit interaction, and can be studied with unbiased numerical techniques. Results will be meaningfully compared with experiments for a variety of compounds.(iv) The PIs will use the time dependent density matrix renormalization group technique to study transport in models for molecules, polymers, transformation of a Mott insulator into a metal, and the sudden expansion of a fermionic gas.This award supports the training of graduate students in advanced computational methods for condensed matter theory and materials research. The research activity involves international collaboration with researchers in Latin America.NON-TECHNICAL SUMMARY:This award supports computational and theoretical research and education on complex materials that exhibit unusual electronic properties and new states of matter which are a consequence of strong interactions among electrons. Using theoretical concepts and advanced computation, the PIs aim to gain insight into new states of matter, effects where small magnetic fields can lead to dramatic changes in the resistance to the flow of electric current, and how charge moves through molecules. They also hope to discover novel magnetic phenomena in semiconductors and semiconductor heterostructures, and more. All these lay the foundations for future technological applications that have the potential to revolutionize electronics and our understanding of certain classes of materials. This activity helps to keep America competitive in the 21st century, not only through intellectual advances but through education of the next generation of scientists able to use computation as a discovery tool and able to function competitively in a global economy.