[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"doc-detail-149977-en":3,"doc-seo-149977-105":30,"detail-sidebar-cat-0-en-105":96},{"code":4,"msg":5,"data":6},0,"success",{"doc_id":7,"user_id":8,"nickname":9,"user_avatar":10,"doc_module":4,"category_id":11,"category_name":12,"doc_title":13,"doc_description":14,"doc_content":15,"file_id":16,"file_url":17,"file_type":18,"file_size":19,"view_count":20,"is_deleted":4,"is_public":20,"is_downloadable":20,"audit_status":20,"page_count":21,"language":22,"language_code":23,"site_id":24,"html_lang":23,"table_of_contents":25,"faqs":26,"seo_title":27,"seo_description":14,"update_tm":28,"read_time":29},149977,962084925502,"Emma Mercer","https://ap-avatar.wpscdn.com/davatar_6f874abed73319feea01a86fa6f0fab8",8,"Research & Report","The Turn of the Screw and the Slide of the Skyrmion - Inaugural Dissertation","The dissertation investigates chiral magnets, focusing on how oscillating magnetic fields can manipulate twisted magnetic phases and isolated skyrmions. Driving a helical phase and a single skyrmion activates translational Goldstone modes at second order in field amplitude, leading to screw-like rotation for helices and constant-velocity sliding for skyrmions. The work also explores electron transport via an Archimedean-screw mechanism, predicts a time quasicrystal instability, and studies fractional topological charges, their scattering properties, and a proposed magnon-powered fractional charge engine.","The Turn of the  \nScrew & the  \nlide of the  \nkyrmion  \nN. del Ser  \n* for the unofficial version with jokes and videos, [contact NdS at ninadelser@gmail.com](contact NdS at ninadelser@gmail.com)  \nThe Turn of the Screw and the Slide of the Skyrmion  \nInaugural-Dissertation  \nzur  \nErlangung des Doktorgrades  \nder Mathematisch-Naturwissenschaftlichen Fakultät der Universität zu Köln  \nvorgelegt von  \nNina del Ser  \ngeboren in  \nColombo, Sri Lanka  \naufgewachsen in  \nAlmaty, Kasachstan und London, Großbritannien  \naus  \nFrankreich und Spanien  \nKöln 2022  \nBerichterstatter: Prof. Dr. Achim Rosch  \nProf. Dr. Sebastian Diehl  \nProf. Dr. Jairo Sinova (externer)  \nVorsitzender der Prüfungskommission: Prof. Dr. Joachim Hemberger  \nTag der mündlichen Prüfung: 3 Juni 2022  \nAll (wo)men by nature desire to know.  \n—Aristotle, tweaked NdS ;)  \nAbstract  \nFor hundreds of years, human beings have developed technologies based on magnetism. From the humble compasses of our ancestors to the smartphones, hard drives and maglev trains that have come to symbolise the modern age, magnets have shaped civilisationsand will continue to do so for generations to come.  \nRecently, physicists have discovered a new class of magnets known as chiral magnets, which are characterised by a lack of inversion symmetry. This property encourages the formation of twisted magnetic structures such as helices and exotic topological particles called skyrmions. Touted as promising candidates for use in future memory storage devices, skyrmions in particular have enjoyed a boom in scientific interest since their experimental discovery over ten years ago.  \nTo use a chiral magnet in a technological setting, we have to interact with it via external forces, for example electric and magnetic fields, heat gradients or currents. In this thesis, we will investigate how chiral magnets can be manipulated by driving them with oscillating magnetic fields. We will do this for both the helical phase and for the single skyrmion, in both cases showing that such driving activates the translational Goldstone modes of the system at second order in the amplitude of the field. Translated into plain English, this means that the magnetic helices start to rotate on their axes at constant speed ωscrew , a type of rotational motion which exactly mimics that of Archimedean screws, while the skyrmion starts to slide like an air hockey puck at constant velocity vslide . We will show how the magnetic Archimedean screw, in particular, can be used as a tool to transport electrons, with the potential of generating large DC electric currents in very clean metallic chiral magnets such as MnSi. We will also see how stronger driving leads to the formation of an interesting “time quasicrystal” instability, where the magnetisation oscillates at temporal and spatial frequencies which are incommensurate with the driving frequency and lattice momentum.  \nWe will also explore the theme of topology, in particular the concept of fractional topological charges in magnets. We will show that such objects exist in both quantisedand non-quantised form, including at the intersections of three or more domain walls orin the remnants of exploding skyrmions. There will be a discussion of their exceptional  \nscattering properties, a feature which distinguishes them from ordinary integer charges which are not able to scatter electrons and magnons. Using these scattering properties we will suggest how to build a magnon-powered fractional charge engine.  \nThe thesis is organised as follows: in chapter 1 we provide an introduction to the chiral magnet model and its different phases, as well as the equation of motion governing magnetisation dynamics. Chapters 2 (“Archimedean screw”), 3 (“Driven skyrmions”) and 4 (“Fractional charges”) then contain the actual research work. We recommend reading chapters 2 and 3 consecutively, as a lot of the ideas for the driven skyrmions project build on the first third or so of the Archimedean ","cbCaisdq2mAXUoUL","https://ap.wps.com/l/cbCaisdq2mAXUoUL","pdf",18240216,1,173,"English","en",105,"# Abstract\n# Contents\n## 1 Model and Fundamentals\n## 2 Archimedean Screw\n## 3 Driven Skyrmions\n## 4 Fractional Charges\n## Conclusion and Outlook","[{\"question\":\"What problem does the thesis address about chiral magnets?\",\"answer\":\"It examines how chiral magnets can be controlled in technological-relevant settings by applying oscillating magnetic fields, including both helical phases and individual skyrmions.\"},{\"question\":\"What does oscillating driving do to the helical phase and skyrmion?\",\"answer\":\"Driving activates translational Goldstone modes at second order in the field amplitude, causing magnetic helices to rotate like Archimedean screws and causing skyrmions to slide at constant velocity.\"},{\"question\":\"How does the thesis connect this physics to electron transport and instabilities?\",\"answer\":\"It shows how the magnetic Archimedean screw can transport electrons, potentially producing large DC currents in clean chiral magnets, and it studies stronger driving that can generate a time quasicrystal instability.\"},{\"question\":\"What role do topology and fractional topological charges play?\",\"answer\":\"The thesis explores fractional topological charges in magnets, including quantised and non-quantised forms, and uses their exceptional scattering properties to propose a magnon-powered fractional charge engine.\"}]","The Turn of the Screw and the Slide of the Skyrmion - Inaugural Dissertation | PDF",1787811138,436,{"code":4,"msg":31,"data":32},"ok",{"site_id":24,"language":23,"slug":33,"title":13,"keywords":34,"description":14,"schema_data":35,"social_meta":91,"head_meta":93,"extra_data":95,"updated_unix":28},"the-turn-of-the-screw-and-the-slide-of-the-skyrmion-inaugural-dissertation","",{"@graph":36,"@context":90},[37,54,69],{"@type":38,"itemListElement":39},"BreadcrumbList",[40,44,48,51],{"item":41,"name":42,"@type":43,"position":20},"https://docshare.wps.com","Home","ListItem",{"item":45,"name":46,"@type":43,"position":47},"https://docshare.wps.com/document/","Document",2,{"item":49,"name":12,"@type":43,"position":50},"https://docshare.wps.com/document/research-report/",3,{"item":52,"name":13,"@type":43,"position":53},"https://docshare.wps.com/document/the-turn-of-the-screw-and-the-slide-of-the-skyrmion-inaugural-dissertation/149977/",4,{"url":52,"name":13,"@type":55,"author":56,"headline":13,"publisher":58,"fileFormat":61,"inLanguage":23,"description":14,"dateModified":62,"datePublished":63,"encodingFormat":61,"isAccessibleForFree":64,"interactionStatistic":65},"DigitalDocument",{"name":9,"@type":57},"Person",{"url":41,"name":59,"@type":60},"DocShare","Organization","application/pdf","2026-09-04","2026-08-27",true,{"@type":66,"interactionType":67,"userInteractionCount":20},"InteractionCounter",{"@type":68},"ViewAction",{"@type":70,"mainEntity":71},"FAQPage",[72,78,82,86],{"name":73,"@type":74,"acceptedAnswer":75},"What problem does the thesis address about chiral magnets?","Question",{"text":76,"@type":77},"It examines how chiral magnets can be controlled in technological-relevant settings by applying oscillating magnetic fields, including both helical phases and individual skyrmions.","Answer",{"name":79,"@type":74,"acceptedAnswer":80},"What does oscillating driving do to the helical phase and skyrmion?",{"text":81,"@type":77},"Driving activates translational Goldstone modes at second order in the field amplitude, causing magnetic helices to rotate like Archimedean screws and causing skyrmions to slide at constant velocity.",{"name":83,"@type":74,"acceptedAnswer":84},"How does the thesis connect this physics to electron transport and instabilities?",{"text":85,"@type":77},"It shows how the magnetic Archimedean screw can transport electrons, potentially producing large DC currents in clean chiral magnets, and it studies stronger driving that can generate a time quasicrystal instability.",{"name":87,"@type":74,"acceptedAnswer":88},"What role do topology and fractional topological charges play?",{"text":89,"@type":77},"The thesis explores fractional topological charges in magnets, including quantised and non-quantised forms, and uses their exceptional scattering properties to propose a magnon-powered fractional charge engine.","https://schema.org",{"og:url":52,"og:type":92,"og:title":13,"og:site_name":59,"og:description":14},"article",{"robots":94,"canonical":52},"index,follow",{"doc_id":7,"site_id":24},{"code":4,"msg":5,"data":97},[98,102,106,110,115,120,125,128,133,136,140],{"id":20,"doc_module":4,"doc_module_name":46,"category_name":99,"show_sort_weight":100,"slug":101},"Story & Novel",90,"story-novel",{"id":47,"doc_module":4,"doc_module_name":46,"category_name":103,"show_sort_weight":104,"slug":105},"Literature",80,"literature",{"id":53,"doc_module":4,"doc_module_name":46,"category_name":107,"show_sort_weight":108,"slug":109},"Exam",70,"exam",{"id":111,"doc_module":4,"doc_module_name":46,"category_name":112,"show_sort_weight":113,"slug":114},5,"Comic",60,"comic",{"id":116,"doc_module":4,"doc_module_name":46,"category_name":117,"show_sort_weight":118,"slug":119},6,"Technology",50,"technology",{"id":121,"doc_module":4,"doc_module_name":46,"category_name":122,"show_sort_weight":123,"slug":124},7,"Healthcare",40,"healthcare",{"id":11,"doc_module":4,"doc_module_name":46,"category_name":12,"show_sort_weight":126,"slug":127},30,"research-report",{"id":129,"doc_module":4,"doc_module_name":46,"category_name":130,"show_sort_weight":131,"slug":132},9,"Religion & Spirituality",20,"religion-spirituality",{"id":131,"doc_module":4,"doc_module_name":46,"category_name":134,"show_sort_weight":131,"slug":135},"World Cup","world-cup",{"id":137,"doc_module":4,"doc_module_name":46,"category_name":138,"show_sort_weight":137,"slug":139},10,"Lifestyle","lifestyle",{"id":141,"doc_module":4,"doc_module_name":46,"category_name":142,"show_sort_weight":111,"slug":143},19,"General","general"]