Topological Materials and Electron Correlations

William Marsh Rice University, Houston TX

Investigators

Abstract

The Condensed Matter and Materials Theory and Condensed Matter Physics Programs jointly contribute support to this award. Non-Technical Summary Over 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 Summary Topological 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.