| 报告题目： |
Topological Vortex Domains in Quantum Materials |
| 报告人： |
Sang-Wook Cheong 教授 |
| 报告人单位： |
Rutgers Center for Emergent Materials
Rutgers, the State University of New Jersey, USA |
| 报告时间： |
2019年6月18日 星期二 15:00-17:00 |
| 报告地点： |
图书馆主馆B区五楼学术报告厅（B501） |
| 邀请人： |
陆成亮教授 |
| 报告人简介： |
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Engineering of domains and domain boundaries is quintessential for technological exploitation of numerous functional materials. However, it has only recently realized that the configuration of these domains/domain boundaries can have vortex topology, and these topological vortex domains are rather common in complex materials as long as long-range interactions such as ferroelastic or dipolar coupling is not dominant. We will discuss a new topological classification scheme of domain/domain boundary configurations: Zm×Zn domains (m directional variants and n translational antiphases) and Zl vortices (where l number of domains and that of domain boundaries merge). This classification, with the concept of topological protection and topological charge conservation, has been applied to a wide range of materials such as improper ferroelectric R(Mn,Fe)O3, antipolar In(Mn,Ga)O3, hybrid improper ferroelectric (Ca,Sr)3Ti2O7, chiral (and ferromagnetic) Fe1/3TaS2, magnetic-superconducting Sr2VO3FeAs, magnetic a-Fe2O3, and CDW systems such as 2H-TaSe2. We will also discuss the emergent physical properties of domain boundaries, distinct from those of domains. The presented topological consideration provides a basis in understanding the formation, kinetics, manipulation and property optimization of domains/domain boundaries in quantum materials. |
| 报告摘要： |
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Sang-Wook Cheong is a Henry Rutgers Professor at Rutgers University, the founding director of the Rutgers Center for Emergent Materials (RCEM), and the founding director of the center for Quantum Materials Synthesis (cQMS), supported by Gordon & Betty Moore Foundation and Rutgers. He was elected fellow of the American Physical Society in 2000, and listed as the 13th most cited physicist for the previous decade in 2003. In 2007 he was awarded the Ho-am Prize in Science (sponsored by Samsung), and the James C. McGroddy Prize of the APS in 2010. He served as a Divisional Associated Editor for Physical Review Letters for 2008-2011, and is currently serving as an Editor of Chief for npj Quantum Materials.
Prof. Cheong’s research activities focus on studies of mesoscopic self-organization in solids, including the nanoscale charge stripe formation, mesoscopic electronic phase separation in mixed-valent transition metal oxides, and the formation of topological vortex domains in improper ferroelectrics. The formation and topology of these self-organized textures can be synergistically relevant to other areas of science such as mathematics (graph theory) and even cosmology. He has also made significant contributions to the research field of enhanced functionalities in complex materials originating from collective correlations such as colossal magnetoresistive and colossal magnetoelectric effects. |
