Topological Materials and Electron Correlations

凝聚态物质和材料理论以及凝聚态物理计划共同为这一奖项提供了支持。非技术总结在过去的几十年里，在材料科学中，“拓扑”的数学概念已经成为一种新的组织原理，它可以确定例如，固体的表面是金属的还是电绝缘的。拓扑是指当材质受到局部扰动时保持不变的全局属性。例如，在存在局部缺陷或污垢的情况下，拓扑材料的性能保持坚固。拓扑材料中电子之间的相互作用可以很弱，也可以很强，因为研究这两类物质的方法不同，两个科学家群体一直在平行研究。这一领域的广度要求社区之间进行互动。这次研讨会的目的是将这两个社区的顶尖专家聚集在一起，突出每个领域的最新成就，并为主题之间的相互交流提供一个论坛。莱斯大学的莱斯量子材料中心将举办为期两天的关于这一主题的研讨会，来自世界各地的顶尖专家和初级研究人员将聚集在一起，他们通过实验探索候选材料，从理论上发展拓扑材料的现象学，并了解强关联的作用。这次研讨会的主要特点是将对拓扑材料感兴趣的弱相关和强相关社区聚集在一起。这将解决理解和探索拓扑物质和强关联之间的交叉的迫切需要。技术摘要近年来，弱关联电子中的拓扑物质取得了重大进展。例如，“高阶”拓扑绝缘体的发现及其潜在的实验实现，磁性有序材料中的Weyl半金属，以及对磁振子拓扑态的探索。与此同时，在过去的几年里，在探索强关联系统的电子拓扑方面取得了快速的进展。例如，在重费米子材料中发现了强关联的Weyl半金属，以及在寻找近藤绝缘体和铁基超导体拓扑态的特征方面取得了进展。在很大程度上，这两个方向一直在发展，但串扰非常有限。现在是促进两个社区之间积极对话的特别时机。研讨会旨在通过将来自弱相关性和强相关性社区的对拓扑材料感兴趣的主要参与者聚集在一起来实现这一目标。为了增加串扰的机会，它将展示各种材料，从涉及sp电子的弱相互作用系统，基于d电子和f电子的强关联化合物，以及包括石墨烯层、液体3He和超冷原子在内的工程结构。选定这些专题时，既考虑到了近年来取得的令人兴奋的程度和进展速度，也考虑到了交叉交流的可能性。经发言者允许，将汇编演讲幻灯片，并以pdf格式在会议结束后从会议网站下载。幻灯片将包括小组讨论的总结结果。该奖项反映了NSF的法定使命，通过使用基金会的学术价值和更广泛的影响审查标准进行评估，被认为是值得支持的。

The Condensed Matter and Materials Theory and Condensed Matter Physics Programs jointly contribute support to this award.Non-Technical SummaryOver the last couple of decades, the mathematical concept of "topology" has emerged as a new organizing principle in the science of materials, one that can determine, for example, whether the surface of a solid is metallic or electrically insulating. Topology refers to global properties that stay the same when a material is perturbed locally. Topological materials properties remain robust, for instance, against the presence of local imperfections or dirt. The interactions between electrons in topological materials can be weak or strong, and, because the methods used to study these two classes differ, two communities of scientists have been working on parallel tracks. The breadth of the field calls for interactions among the communities. This workshop aims to bring together top experts from these two communities to highlight the recent achievements in each area and to provide a forum for cross-talk between the subjects. Rice University's Rice Center for Quantum Materials will host a two-day workshop on this topic, bringing together top experts and junior researchers from around the globe who probe experimentally candidate materials, develop theoretically the phenomenology of topological materials, and understand the role of strong correlations. The key distinguishing feature of this workshop will be to bring together the weakly and strongly correlated communities interested in topological materials. This will address an acute need to understand and explore the intersection between topological matter and strong correlations.Technical SummaryTopological matter in weakly correlated electrons has seen major advances in recent years. Examples include the discovery of "higher-order" topological insulators and their potential experimental realization, Weyl semimetals in magnetically ordered materials, and explorations of topological states of magnons. Meanwhile, rapid progress has taken place during the last couple of years in exploring electronic topology of strongly correlated systems. Examples include the discovery of strongly correlated Weyl semimetals in heavy-Fermion materials and progress in the search for signatures of topological states in Kondo insulators and iron-based superconductors. For the most part, the two directions have been developing with very limited crosstalk. Now is a particularly opportune time to foster active dialogue between the two communities. The workshop aims to realize this goal by bringing together key players interested in topological materials from the communities of both weak and strong correlations. To enhance the opportunities for crosstalk, it will feature a variety of materials, ranging from weakly interacting systems involving sp-electrons, strongly correlated compounds based on d- and f- electrons, engineered structures including graphene layers, liquid 3He and ultracold atoms. The topics have been chosen with a view to both the level of excitement and the pace of advances that have been made in recent years, as well as by the potential for cross fertilization.With permission from the speakers, the slides from the talks will be compiled and made available for download in pdf form from the meeting website following the conclusion of the meeting. The slides will include the summary outcomes of the group discussions. The participants will be encouraged to use these as a springboard for graduate education about these problems at their institutions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.