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和教育。 这项工作涉及算法开发，大规模计算，以及使用计算作为发现工具。研究的主要内容包括：（1）重点论证双交换族微观材料中的巨磁电阻效应。PI的目的是包括在蒙特卡罗模拟的所有成分被认为是重要的，以解释这种现象，洪特耦合，声子，超交换，和淬火无序。(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处发生电子重构。这些效应表明，半导体异质结构的类似物可以使用复合氧化物开发。PI将探索各种界面，包括锰氧化物-锰氧化物，超导体-锰氧化物和锰氧化物-钛酸盐。这些人工制备的系统的性能将进行研究。(iii)PI将研究稀磁半导体的真实的空间模型，该模型再现了母体化合物的价带，考虑了随机锰掺杂和自旋轨道相互作用，并且可以用无偏数值技术进行研究。结果将与各种化合物的实验进行有意义的比较。(iv)PI将使用含时密度矩阵重整化群技术来研究分子、聚合物、莫特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的高级计算方法方面的培训。非技术概要：该奖项支持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特性和新的物质状态，这些都是电子之间强相互作用的结果。使用理论概念和先进的计算，PI旨在深入了解物质的新状态，小磁场可能导致电流流动阻力发生巨大变化的影响，以及电荷如何通过分子移动。他们还希望在半导体和半导体异质结构中发现新的磁性现象。所有这些都为未来的技术应用奠定了基础，这些技术应用有可能彻底改变电子产品和我们对某些类别材料的理解。这项活动有助于保持美国在21世纪世纪的竞争力，不仅通过智力进步，而且通过教育下一代科学家能够使用计算作为发现工具，并能够在全球经济中发挥竞争力。

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.