4d and 5d Transition Metal Oxides: A New Frontier of Materials with Exotic Phenomena

在过去的十年里，对新型电子材料的广泛而深入的研究已经越来越清楚地表明，相互作用的电子组装的行为通常会以完全出乎意料的现象使我们感到惊讶，这需要进一步的实验和理论探索。 被称为过渡金属氧化物的材料是一类新的电子材料，最近已经揭示了大量奇异的物理现象，甚至一些挑战传统物理学基本原理的悖论。 这些现象反映了新的物理学，并提出了深刻的智力挑战。 正是这些挑战为我们进一步开展这些研究提供了强大的动力，这些研究是目前凝聚态物理领域最重要和最有趣的研究之一。 近年来，美国在凝聚态物理学领域的领导地位受到侵蚀，部分原因是缺乏专门从事合成和表征新材料的材料物理学家。 拟议的项目将通过提供严格的培训来填补这一空白，该培训强调在同一实验室中进行材料合成和表征。 此外，该项目将通过引进现代技术和设备，帮助吸引年轻人学习物理科学。 这一点尤为紧迫和重要，因为我们正在进入一个高科技时代，美国的物理科学本科生数量稳步下降，而这些本科生是推动经济发展的技术领域的未来人力资本。4d和5d过渡金属氧化物作为一类新的关联电子系统，最近揭示了大量奇异的电子相、磁相和轨道相，甚至一些悖论，挑战了传统物理学的基本原理。该项目的目标是继续我们对这些材料的实验研究，以进一步解决目前凝聚态物理领域最重要和最有趣的问题。这些材料的特点是电荷、自旋和轨道自由度之间的强相互作用以及对小扰动的高灵敏度。它们不仅涵盖了凝聚态物理学中的几乎每一个状态，而且还展示了在其他材料中没有或很少发现的各种非凡现象。这些现象反映了新的物理学，并提出了深刻的挑战。正是这些挑战为我们进一步开展这些研究提供了强大的动力。该项目包括一个系统的努力，阐明这些材料的基本物理以及寻找具有有趣特性的新材料。研究活动范围从单晶生长到表征作为温度、磁场、压力和化学成分的函数的结构、传输和热力学性质。参与的研究生将在同一实验室接受严格的培训，强调材料合成和表征。

Non-Technical Abstract The extensive and intensive research on novel electronic materials in the last decade has made it increasingly clear that the behavior of an assembly of interacting electrons will routinely surprise us with entirely unexpected phenomena that call for further experimental and theoretical exploration. The materials known as transition metal oxides are a class of new electronic materials that recently have revealed a large array of exotic physical phenomena and even some paradoxes that challenge the very fundamentals of conventional physics. These phenomena reflect new physics and present profound intellectual challenges. It is these challenges that provide strong motivation for us to further pursue these studies, which are currently among the most important and interesting in the field of Condensed Matter Physics. The US leadership in Condensed Matter Physics has been eroded in recent years due in part to the lack of materials physicists who specialize in both synthesizing and characterizing new materials. The proposed project will help fill this gap by providing rigorous training that emphasizes both materials synthesis and characterization in the same lab. In addition, this project will help draw young minds to physical sciences by introducing modern techniques and equipment. This is particularly urgent and important as we are entering an era of high technologies with steadily declining numbers of physical sciences undergraduates in the US who are the future human capital in technologies that drive the economy. Technical AbstractThe 4d and 5d transition metal oxides as a class of new correlated electron systems have recently revealed a large array of exotic electronic, magnetic and orbital phases and even some paradoxes that challenge the very fundamentals of conventional physics. The objective of this project is to continue our experimental investigation of these materials to further address issues that are currently among the most important and interesting in the field of Condensed Matter Physics. These materials are characterized by the strong interplay of charge, spin and orbital degrees of freedom and the high sensitivity to small perturbations. They not only cover almost every state in Condensed Matter Physics but also exhibit a wide array of extraordinary phenomena not or rarely found in other materials. These phenomena reflect new physics and present profound challenges. It is these challenges that provide strong motivation for us to further pursue these studies. The project encompasses a systematic effort to elucidate the underlying physics of these materials as well as a search for new materials with interesting properties. Research activities range from single crystal growth to characterization of structural, transport and thermodynamic properties as a function of temperature, magnetic field, pressure and chemical composition. Graduate students involved will receive rigorous training that emphasizes both materials synthesis and characterization in the same lab.