{"id":404,"date":"2022-10-03T17:17:09","date_gmt":"2022-10-03T21:17:09","guid":{"rendered":"https:\/\/sciences.ucf.edu\/physics\/afmspin\/?p=404"},"modified":"2022-10-04T15:08:59","modified_gmt":"2022-10-04T19:08:59","slug":"unconventional-spin-orbit-torques-and-high-frequency-exchange-resonance-in-2d-antiferromagnetic-topological-insulators","status":"publish","type":"post","link":"https:\/\/sciences.ucf.edu\/physics\/afmspin\/unconventional-spin-orbit-torques-and-high-frequency-exchange-resonance-in-2d-antiferromagnetic-topological-insulators\/","title":{"rendered":"Unconventional spin-orbit torques and high-frequency exchange resonance in 2D antiferromagnetic topological insulators"},"content":{"rendered":"<p><img fetchpriority=\"high\" decoding=\"async\" class=\" wp-image-405 aligncenter\" src=\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/wp-content\/uploads\/sites\/31\/2022\/10\/FIG1PhysRevB.106.054418-300x191.png\" alt=\"\" width=\"487\" height=\"310\" srcset=\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/wp-content\/uploads\/sites\/31\/2022\/10\/FIG1PhysRevB.106.054418-300x191.png 300w, https:\/\/sciences.ucf.edu\/physics\/afmspin\/wp-content\/uploads\/sites\/31\/2022\/10\/FIG1PhysRevB.106.054418.png 500w\" sizes=\"(max-width: 487px) 100vw, 487px\" \/><\/p>\n<p>Recent developments in magnetic topological insulators (MTI) such as antiferromagnetic MnBi<sub>2<\/sub>Te<sub>4<\/sub> opened new arenas for electric control of magnetization dynamics. PI-Cheng\u2019s group formulated the spin-orbit torque (SOT) arising from the topological electrons in antiferromagnetic MTI as well as its reciprocal effect\u2014topological charge pumping. For undoped MnBi<sub>2<\/sub>Te<sub>4<\/sub>, the SOT originates from the adiabatic current of valence electrons, which does not incur Joule heating as ordinary current-induced torques. The proposed SOT acts oppositely on two neighboring magnetic layers, whereby an applied AC electric field can drive the resonance of the exchange mode with a frequency lying in the sub-THz regime. The SOT-induced exchange resonance manifests as a sharp peak in the effective optical conductivity, entailing a remarkably weaker energy dissipation compared to ordinary ferromagnetic and antiferromagnetic resonances driven by conventional SOT. In trilayer antiferromagnetic MnBi<sub>2<\/sub>Te<sub>4<\/sub>, a hitherto unknown exchange resonance lying in the sub-THz regime is predicted, which does not react to microwave radiations but can only be driven by the unconventional SOT in MTI. This works opens new pathways to manipulate MnBi<sub>2<\/sub>Te<sub>4<\/sub> and similar antiferromagnetic MTIs by electrical means.<\/p>\n<p>This theoretical work has been published in Physical Review B and is available <a href=\"https:\/\/journals.aps.org\/prb\/abstract\/10.1103\/PhysRevB.106.054418\">here<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Recent developments in magnetic topological insulators (MTI) such as antiferromagnetic MnBi2Te4 opened new arenas for electric control of magnetization dynamics. PI-Cheng\u2019s group formulated the spin-orbit torque (SOT) arising from the <a class=\"more-link\" href=\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/unconventional-spin-orbit-torques-and-high-frequency-exchange-resonance-in-2d-antiferromagnetic-topological-insulators\/\">Continue Reading &rarr;<\/a><\/p>\n","protected":false},"author":84,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_links_to":"","_links_to_target":""},"categories":[7],"tags":[],"class_list":["post-404","post","type-post","status-publish","format-standard","hentry","category-publications"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.2 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Unconventional spin-orbit torques and high-frequency exchange resonance in 2D antiferromagnetic topological insulators -<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/unconventional-spin-orbit-torques-and-high-frequency-exchange-resonance-in-2d-antiferromagnetic-topological-insulators\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Unconventional spin-orbit torques and high-frequency exchange resonance in 2D antiferromagnetic topological insulators -\" \/>\n<meta property=\"og:description\" content=\"Recent developments in magnetic topological insulators (MTI) such as antiferromagnetic MnBi2Te4 opened new arenas for electric control of magnetization dynamics. PI-Cheng\u2019s group formulated the spin-orbit torque (SOT) arising from the Continue Reading &rarr;\" \/>\n<meta property=\"og:url\" content=\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/unconventional-spin-orbit-torques-and-high-frequency-exchange-resonance-in-2d-antiferromagnetic-topological-insulators\/\" \/>\n<meta property=\"article:published_time\" content=\"2022-10-03T21:17:09+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2022-10-04T19:08:59+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/wp-content\/uploads\/sites\/31\/2022\/10\/FIG1PhysRevB.106.054418-300x191.png\" \/>\n<meta name=\"author\" content=\"Gregory Fritjofson\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Gregory Fritjofson\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/unconventional-spin-orbit-torques-and-high-frequency-exchange-resonance-in-2d-antiferromagnetic-topological-insulators\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/unconventional-spin-orbit-torques-and-high-frequency-exchange-resonance-in-2d-antiferromagnetic-topological-insulators\/\"},\"author\":{\"name\":\"Gregory Fritjofson\",\"@id\":\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/#\/schema\/person\/dfe9c061eec5b3ae750208f34e51ca90\"},\"headline\":\"Unconventional spin-orbit torques and high-frequency exchange resonance in 2D antiferromagnetic topological insulators\",\"datePublished\":\"2022-10-03T21:17:09+00:00\",\"dateModified\":\"2022-10-04T19:08:59+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/unconventional-spin-orbit-torques-and-high-frequency-exchange-resonance-in-2d-antiferromagnetic-topological-insulators\/\"},\"wordCount\":210,\"image\":{\"@id\":\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/unconventional-spin-orbit-torques-and-high-frequency-exchange-resonance-in-2d-antiferromagnetic-topological-insulators\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/wp-content\/uploads\/sites\/31\/2022\/10\/FIG1PhysRevB.106.054418-300x191.png\",\"articleSection\":[\"Publications\"],\"inLanguage\":\"en-US\"},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/unconventional-spin-orbit-torques-and-high-frequency-exchange-resonance-in-2d-antiferromagnetic-topological-insulators\/\",\"url\":\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/unconventional-spin-orbit-torques-and-high-frequency-exchange-resonance-in-2d-antiferromagnetic-topological-insulators\/\",\"name\":\"Unconventional spin-orbit torques and high-frequency exchange resonance in 2D antiferromagnetic topological insulators -\",\"isPartOf\":{\"@id\":\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/unconventional-spin-orbit-torques-and-high-frequency-exchange-resonance-in-2d-antiferromagnetic-topological-insulators\/#primaryimage\"},\"image\":{\"@id\":\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/unconventional-spin-orbit-torques-and-high-frequency-exchange-resonance-in-2d-antiferromagnetic-topological-insulators\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/wp-content\/uploads\/sites\/31\/2022\/10\/FIG1PhysRevB.106.054418-300x191.png\",\"datePublished\":\"2022-10-03T21:17:09+00:00\",\"dateModified\":\"2022-10-04T19:08:59+00:00\",\"author\":{\"@id\":\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/#\/schema\/person\/dfe9c061eec5b3ae750208f34e51ca90\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/unconventional-spin-orbit-torques-and-high-frequency-exchange-resonance-in-2d-antiferromagnetic-topological-insulators\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/unconventional-spin-orbit-torques-and-high-frequency-exchange-resonance-in-2d-antiferromagnetic-topological-insulators\/#primaryimage\",\"url\":\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/wp-content\/uploads\/sites\/31\/2022\/10\/FIG1PhysRevB.106.054418.png\",\"contentUrl\":\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/wp-content\/uploads\/sites\/31\/2022\/10\/FIG1PhysRevB.106.054418.png\",\"width\":500,\"height\":319,\"caption\":\"Diagram with two parts: (a) 3D visualization showing two FM layers and a central TI layer with vectors indicating magnetization directions. (b) Energy diagrams showing four distinct potential wells labeled 1 to 4.\"},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/#website\",\"url\":\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/\",\"name\":\"\",\"description\":\"\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Person\",\"@id\":\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/#\/schema\/person\/dfe9c061eec5b3ae750208f34e51ca90\",\"name\":\"Gregory Fritjofson\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/secure.gravatar.com\/avatar\/d69d9a6f73b3b6c0bcb07d2dccdb90a51eddff27039cbb9b8475a2c1fa28df07?s=96&d=mm&r=g\",\"url\":\"https:\/\/secure.gravatar.com\/avatar\/d69d9a6f73b3b6c0bcb07d2dccdb90a51eddff27039cbb9b8475a2c1fa28df07?s=96&d=mm&r=g\",\"contentUrl\":\"https:\/\/secure.gravatar.com\/avatar\/d69d9a6f73b3b6c0bcb07d2dccdb90a51eddff27039cbb9b8475a2c1fa28df07?s=96&d=mm&r=g\",\"caption\":\"Gregory Fritjofson\"},\"url\":\"https:\/\/sciences.ucf.edu\/physics\/afmspin\/author\/gr464854\/\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Unconventional spin-orbit torques and high-frequency exchange resonance in 2D antiferromagnetic topological insulators -","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/sciences.ucf.edu\/physics\/afmspin\/unconventional-spin-orbit-torques-and-high-frequency-exchange-resonance-in-2d-antiferromagnetic-topological-insulators\/","og_locale":"en_US","og_type":"article","og_title":"Unconventional spin-orbit torques and high-frequency exchange resonance in 2D antiferromagnetic topological insulators -","og_description":"Recent developments in magnetic topological insulators (MTI) such as antiferromagnetic MnBi2Te4 opened new arenas for electric control of magnetization dynamics. 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