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

过去十年对新型电子材料的广泛而深入的研究日益清楚地表明，相互作用电子的集合的行为通常会以完全意想不到的现象令我们惊讶，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，最近揭示了大量奇异的物理现象，甚至一些悖论，挑战了传统物理学的基本原理。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中最重要和最有趣的研究之一。近年来，美国在凝聚态物理领域的领导地位有所削弱，部分原因是缺乏专门从事新材料合成和表征的材料物理学家。拟议的项目将通过在同一实验室提供强调材料合成和表征的严格培训来帮助填补这一空白。此外，该项目将通过引入现代技术和设备，帮助吸引年轻人对物理科学感兴趣。这一点尤为紧迫和重要，因为我们正进入一个高科技时代，美国理科本科生的数量稳步下降，他们是推动经济增长的技术领域的未来人力资本。技术摘要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，甚至出现了一些悖论，挑战了传统物理学的基本原理。这个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中最重要和最有趣的问题。这些材料的特点是电荷、自旋和轨道自由度的强烈相互作用，以及对微小扰动的高度敏感性。它们不仅涵盖了凝聚态物理中的几乎每一种态，而且还展示了一系列其他材料中没有或很少出现的特殊现象。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。该项目包括一项系统的努力，以阐明这些材料的潜在物理原理，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结构、输运和热力学性质，作为温度、磁场、压力和化学成分的函数。参与其中的研究生将在同一实验室接受严格的培训，同时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.