{"673465":{"#nid":"673465","#data":{"type":"event","title":"Transporting the Shape of Spin: From Spintronics to Multipoletronics","body":[{"value":"\u003Cp\u003E\u003Cspan\u003E\u003Cspan\u003EHua Chen is a condensed matter theorist interested in a wide range of topics in magnetism, superconductivity, topology, and low-dimensional materials, etc., in particular in those related to spin-orbit coupling. He is currently an Associate Professor in the Physics Department and the School of Materials Science and Engineering at Colorado State University. Previously he was a Postdoctoral Fellow at the Physics Department of The University of Texas at Austin. He got his PhD in 2012 at the University of Tennessee at Knoxville and his BS in 2006 at Zhengzhou University. He received the NSF CAREER award in 2020.\u003C\/span\u003E\u003C\/span\u003E\u003C\/p\u003E\r\n","summary":"","format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003E\u003Cspan\u003E\u003Cspan\u003EThe mechanisms of these processes are often captured qualitatively by treating spin as a conserved quantity. However, in materials that exhibit strong spintronics phenomena, such an approximation is frequently questionable. This dilemma leads us to pose the following question: Can conduction electrons carry physical observables other than spin, even if these observables are not strictly conserved, and give rise to new measurable phenomena? In this talk, I will introduce the language and tools for defining and calculating spin magnetic multipole moments of Bloch electrons in a gauge-invariant manner [1]. These magnetic multipole moments are inherently local in both real and momentum spaces, achieved through a wave-packet approach. One can then introduce a semiclassical Boltzmann theory to describe the transport of these multipole moments. Using monolayer phosphorene as a prototypical example, I will elucidate some physical consequences of spin magnetic multipole moments generated by electric fields and currents, in particular current-induced spin accumulation with staggered signs at corners of a square sample. Additionally, I will discuss how the spin Hall effect can be understood as an electrical response of spin magnetic quadrupole moment or spin density polarization [2]. In the end I will briefly mention our ongoing work on the modern theory of equilibrium higher-order spin magnetic multipole moments [3].\u003C\/span\u003E\u003C\/span\u003E\u003C\/p\u003E\r\n\r\n\u003Cp\u003E\u003Cspan\u003E\u003Cspan\u003E[1] M. Tahir and HC, Phys. Rev. Lett. 131, 106701 (2023)\u003Cbr \/\u003E\r\n[2] HC, Q. Niu, and A. H. MacDonald, arXiv:1803.01294\u003Cbr \/\u003E\r\n[3] HC, G.-Y. Guo, D. Xiao, in preparation.\u003C\/span\u003E\u003C\/span\u003E\u003C\/p\u003E\r\n","format":"limited_html"}],"field_summary_sentence":[{"value":"Significant developments in spintronics over the past decades have established that electron spin can be transported and manipulated by electrical means."}],"uid":"36562","created_gmt":"2024-03-12 13:04:29","changed_gmt":"2024-03-12 13:04:28","author":"tnevels9","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2024-04-03T14:00:00-04:00","event_time_end":"2024-04-03T16:00:00-04:00","event_time_end_last":"2024-04-03T16:00:00-04:00","gmt_time_start":"2024-04-03 18:00:00","gmt_time_end":"2024-04-03 20:00:00","gmt_time_end_last":"2024-04-03 20:00:00","rrule":null,"timezone":"America\/New_York"},"location":"Howey Building N110","extras":[],"hg_media":{"673362":{"id":"673362","type":"image","title":"Hua-Chen-4-1536x1024.jpg","body":null,"created":"1710248628","gmt_created":"2024-03-12 13:03:48","changed":"1710248608","gmt_changed":"2024-03-12 13:03:28","alt":"Hua Chen","file":{"fid":"256748","name":"Hua-Chen-4-1536x1024.jpg","image_path":"\/sites\/default\/files\/2024\/03\/12\/Hua-Chen-4-1536x1024.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/2024\/03\/12\/Hua-Chen-4-1536x1024.jpg","mime":"image\/jpeg","size":238112,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/2024\/03\/12\/Hua-Chen-4-1536x1024.jpg?itok=9Q5x0buf"}}},"media_ids":["673362"],"groups":[{"id":"126011","name":"School of Physics"}],"categories":[],"keywords":[{"id":"166937","name":"School of Physics"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1795","name":"Seminar\/Lecture\/Colloquium"}],"invited_audience":[{"id":"78761","name":"Faculty\/Staff"},{"id":"174045","name":"Graduate students"},{"id":"177814","name":"Postdoc"},{"id":"78751","name":"Undergraduate students"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[],"email":[],"slides":[],"orientation":[],"userdata":""}}}