{"690834":{"#nid":"690834","#data":{"type":"event","title":"School of Physics Fall Colloquium Series- Dr. Mark Dean(BNL)","body":[{"value":"\u003Cp\u003E\u003Cstrong\u003ESpeaker: \u003C\/strong\u003EDr. Mark Dean(BNL)\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EHost: \u003C\/strong\u003EYao Wang\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ETitle: \u003C\/strong\u003EExploring many-body excitons with resonant inelastic X\u2011ray scattering\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EAbstract:\u003C\/strong\u003E Excitons\u2014correlated electron\u2013hole pairs\u2014play a central role in the optical and electronic properties of solids. In quantum materials, strong electronic correlations and exchange interactions can produce unconventional\u0026nbsp;many-body excitons whose momentum dependence, symmetry, and coupling to magnetism remain poorly\u0026nbsp;understood. In this talk, I will show how resonant inelastic X-ray scattering (RIXS) [1], with its combined\u0026nbsp;sensitivity to energy, momentum, and excitation symmetry, provides a powerful view of these states. I will\u0026nbsp;discuss magnetically propagating Hund\u2019s excitons in NiPS3 [2], dispersive dark excitons in CrI3 [3], and\u0026nbsp;anisotropic excitonic states in CrSBr [4]. Together, these results illustrate how excitons can encode and\u0026nbsp;transmit the intertwined spin, orbital, and charge character of quantum materials. I will conclude with an\u0026nbsp;outlook on using ultrafast pump\u2013probe RIXS to create and track such states away from equilibrium.\u003C\/p\u003E\u003Ch6\u003E\u003Cstrong\u003EReferences\u003C\/strong\u003E\u003C\/h6\u003E\u003Ch6\u003E[1] M. Mitrano, S. Johnston, Y.-J. Kim, and M. P. M. Dean, Exploring Quantum Materials with Resonant Inelastic X-Ray Scattering, Phys. Rev.\u0026nbsp;\u003Cbr\u003EX 14, 40501 (2024).\u003C\/h6\u003E\u003Ch6\u003E[2] W. He, Y. Shen, K. Wohlfeld, J. Sears, J. Li, J. Pelliciari, M. Walicki, S. Johnston, E. Baldini, V. Bisogni, M. Mitrano, and M. P. M. Dean,\u0026nbsp;\u003Cbr\u003EMagnetically propagating Hund\u0027s exciton in van der Waals antiferromagnet NiPS3\u003Cbr\u003E, Nature Communications 15, 3496 (2024).\u003C\/h6\u003E\u003Ch6\u003E[3] W. He, J. Sears, F. Barantani, T. Kim, J. W. Villanova, T. Berlijn, M. Lajer, M. A. McGuire, J. Pelliciari, V. Bisogni, S. Johnston, E. Baldini, M.\u0026nbsp;\u003Cbr\u003EMitrano, and M. P. M. Dean, Dispersive Dark Excitons in van der Waals Ferromagnet CrI3\u003Cbr\u003E, Phys. Rev. X 15, 11042 (2025).\u003C\/h6\u003E\u003Ch6\u003E[4] J. Sears, B. Zager, W. He, C. A. Occhialini, Y. Shen, M. Lajer, J. W. Villanova, T. Berlijn, F. Yakhou-Harris, N. B. Brookes, D. G. Chica, X. Roy,\u0026nbsp;\u003Cbr\u003EE. Baldini, J. Pelliciari, V. Bisogni, S. Johnston, M. Mitrano, and M. P. M. Dean, Observation of Anisotropic Dispersive Dark-Exciton\u0026nbsp;\u003Cbr\u003EDynamics in CrSBr, Phys. Rev. Lett. 135, 146503 (2025).\u003C\/h6\u003E\u003Cdiv\u003E\u0026nbsp;\u003C\/div\u003E\u003Cp\u003E\u003Cstrong\u003EBio:\u003C\/strong\u003E I am the X-ray Scattering Group Leader at Brookhaven and run a research program that focuses on resonant\u0026nbsp;inelastic X-ray scattering (RIXS) of quantum materials. My research interests include complex oxides, strongly\u0026nbsp;spin\u2013orbit-coupled materials, quantum heterostructures, non-equilibrium states, and topology in crystalline\u0026nbsp;materials. I earned my PhD from the University of Cambridge in 2010. My work has been recognized with a\u0026nbsp;Department of Energy Early Career Award in 2014 and the Distinction of Tenure from Brookhaven in 2022,\u0026nbsp;and I currently serve on the editorial board of Physical Review X.\u003C\/p\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E","summary":"","format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003E\u003Cstrong\u003EAbstract:\u003C\/strong\u003E Excitons\u2014correlated electron\u2013hole pairs\u2014play a central role in the optical and electronic properties of solids.\u0026nbsp;In quantum materials, strong electronic correlations and exchange interactions can produce unconventional\u0026nbsp;many-body excitons whose momentum dependence, symmetry, and coupling to magnetism remain poorly\u0026nbsp;understood. In this talk, I will show how resonant inelastic X-ray scattering (RIXS) [1], with its combined\u0026nbsp;sensitivity to energy, momentum, and excitation symmetry, provides a powerful view of these states. I will\u0026nbsp;discuss magnetically propagating Hund\u2019s excitons in NiPS3 [2], dispersive dark excitons in CrI3 [3], and\u0026nbsp;anisotropic excitonic states in CrSBr [4]. Together, these results illustrate how excitons can encode and\u0026nbsp;transmit the intertwined spin, orbital, and charge character of quantum materials. I will conclude with an\u0026nbsp;outlook on using ultrafast pump\u2013probe RIXS to create and track such states away from equilibrium.\u003C\/p\u003E\u003Ch6\u003E\u003Cstrong\u003EReferences\u003C\/strong\u003E\u003C\/h6\u003E\u003Ch6\u003E[1] M. Mitrano, S. Johnston, Y.-J. Kim, and M. P. M. Dean, Exploring Quantum Materials with Resonant Inelastic X-Ray Scattering, Phys. Rev.\u0026nbsp;\u003Cbr\u003EX 14, 40501 (2024).\u003C\/h6\u003E\u003Ch6\u003E[2] W. He, Y. Shen, K. Wohlfeld, J. Sears, J. Li, J. Pelliciari, M. Walicki, S. Johnston, E. Baldini, V. Bisogni, M. Mitrano, and M. P. M. Dean,\u0026nbsp;\u003Cbr\u003EMagnetically propagating Hund\u0027s exciton in van der Waals antiferromagnet NiPS3\u003Cbr\u003E, Nature Communications 15, 3496 (2024).\u003C\/h6\u003E\u003Ch6\u003E[3] W. He, J. Sears, F. Barantani, T. Kim, J. W. Villanova, T. Berlijn, M. Lajer, M. A. McGuire, J. Pelliciari, V. Bisogni, S. Johnston, E. Baldini, M.\u0026nbsp;\u003Cbr\u003EMitrano, and M. P. M. Dean, Dispersive Dark Excitons in van der Waals Ferromagnet CrI3\u003Cbr\u003E, Phys. Rev. X 15, 11042 (2025).\u003C\/h6\u003E\u003Ch6\u003E[4] J. Sears, B. Zager, W. He, C. A. Occhialini, Y. Shen, M. Lajer, J. W. Villanova, T. Berlijn, F. Yakhou-Harris, N. B. Brookes, D. G. Chica, X. Roy,\u0026nbsp;\u003Cbr\u003EE. Baldini, J. Pelliciari, V. Bisogni, S. Johnston, M. Mitrano, and M. P. M. Dean, Observation of Anisotropic Dispersive Dark-Exciton\u0026nbsp;\u003Cbr\u003EDynamics in CrSBr, Phys. Rev. Lett. 135, 146503 (2025).\u003C\/h6\u003E\u003Ch6\u003E\u0026nbsp;\u003C\/h6\u003E\u003Ch5\u003E\u003Cbr\u003E\u0026nbsp;\u003C\/h5\u003E\u003Ch5\u003E\u0026nbsp;\u003C\/h5\u003E\u003Ch6\u003E\u0026nbsp;\u003C\/h6\u003E\u003Ch6\u003E\u0026nbsp;\u003C\/h6\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Dr. Mark Dean(BNL) Exploring many-body excitons with resonant inelastic  X\u2011ray scattering"}],"uid":"36632","created_gmt":"2026-06-22 13:37:27","changed_gmt":"2026-10-02 14:11:47","author":"tkendall8","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2026-10-12T15:30:00-04:00","event_time_end":"2026-10-12T16:30:00-04:00","event_time_end_last":"2026-10-12T16:30:00-04:00","gmt_time_start":"2026-10-12 19:30:00","gmt_time_end":"2026-10-12 20:30:00","gmt_time_end_last":"2026-10-12 20:30:00","rrule":null,"timezone":"America\/New_York"},"location":"Marcus Nanotechnology room 1116-1118","extras":[],"groups":[{"id":"126011","name":"School of Physics"}],"categories":[],"keywords":[],"core_research_areas":[],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[],"email":[],"slides":[],"orientation":[],"userdata":""}}}