{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/122172"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/122172","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Disorder and diffuse scattering in single-chirality (TaSe4)2I crystals","abstract":"Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2025-12-01","abstract_html":"Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2025-12-01","abstract_has_math":false,"creators":["Christensen, Jacob Andrew"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Materials Science & Engr","degree_department":null,"school":null,"contributors":["Shoemaker, Daniel P"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2023,"date_issued":"2023-12","date_published":"2023-12","updated_at":"2026-07-22T22:25:00Z","subjects":["Charge Density Waves","Peierls Transition","Topological Materials","Pump-probe Spectroscopy","Scanning Transmission Electron Microscopy","X-ray Diffraction","Chiral Symmetry","Lattice Modeling"],"languages":["en","eng"],"rights":["Copyright 2023 Jacob Andrew Christensen"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2142/122172","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Shoemaker, Daniel P"]},{"key":"dc:creator","label":"Author","values":["Christensen, Jacob Andrew"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2023-12","2023-12-05"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Materials Science & Engr"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Charge Density Waves","Peierls Transition","Topological Materials","Pump-probe Spectroscopy","Scanning Transmission Electron Microscopy","X-ray Diffraction","Chiral Symmetry","Lattice Modeling"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en","eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2023 Jacob Andrew Christensen"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2142/122172"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2025-12-01","The student, Jacob Christensen, accepted the attached license on 2023-12-03 at 17:55.","The student, Jacob Christensen, submitted this Thesis for approval on 2023-12-03 at 18:20.","This Thesis was approved for publication on 2023-12-05 at 10:35.","DSpace SAF Submission Ingestion Package generated from Vireo submission #20120 on 2024-03-01 at 13:32:37","The quasi-one-dimensional chiral compound (TaSe4)2I has been extensively studied as a prime example of a topological Weyl semimetal. Upon crossing its phase transition temperature T_CDW ≈ 263 K, (TaSe4)2I exhibits incommensurate charge density wave (CDW) modulations described by the well-defined propagation vector ∼(0.05, 0.05, 0.11), oblique to the TaSe4 chains. Although optical and transport properties greatly depend on chirality, there is no systematic report about chiral domain size for (TaSe4)2I. In this study, our single-crystal scattering refinements reveal a bulk iodine deficiency, and Flack parameter measurements on multiple crystals demonstrate that separate (TaSe4)2I crystals have uniform handedness, supported by direct imaging and helicity dependent THz emission spectroscopy. Our single-crystal X-ray scattering and calculated diffraction patterns identify multiple diffuse features and create a real-space picture of the temperature-dependent (TaSe4)2I crystal structure. The short-range diffuse features are present at room temperature and decrease in intensity as the CDW modulation develops. These transverse displacements, along with electron pinning from the iodine deficiency, help explain why (TaSe4)2I behaves as an electronic semiconductor at temperatures above and below T_CDW, despite a metallic band structure calculated from density functional theory of the ideal structure."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Disorder and diffuse scattering in single-chirality (TaSe4)2I crystals"]}]}],"canonical_facts":{"dc:contributor":["Shoemaker, Daniel P"],"dc:creator":["Christensen, Jacob Andrew"],"dc:date":["2023-12","2023-12-05"],"dc:description":["Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2025-12-01","The student, Jacob Christensen, accepted the attached license on 2023-12-03 at 17:55.","The student, Jacob Christensen, submitted this Thesis for approval on 2023-12-03 at 18:20.","This Thesis was approved for publication on 2023-12-05 at 10:35.","DSpace SAF Submission Ingestion Package generated from Vireo submission #20120 on 2024-03-01 at 13:32:37","The quasi-one-dimensional chiral compound (TaSe4)2I has been extensively studied as a prime example of a topological Weyl semimetal. Upon crossing its phase transition temperature T_CDW ≈ 263 K, (TaSe4)2I exhibits incommensurate charge density wave (CDW) modulations described by the well-defined propagation vector ∼(0.05, 0.05, 0.11), oblique to the TaSe4 chains. Although optical and transport properties greatly depend on chirality, there is no systematic report about chiral domain size for (TaSe4)2I. In this study, our single-crystal scattering refinements reveal a bulk iodine deficiency, and Flack parameter measurements on multiple crystals demonstrate that separate (TaSe4)2I crystals have uniform handedness, supported by direct imaging and helicity dependent THz emission spectroscopy. Our single-crystal X-ray scattering and calculated diffraction patterns identify multiple diffuse features and create a real-space picture of the temperature-dependent (TaSe4)2I crystal structure. The short-range diffuse features are present at room temperature and decrease in intensity as the CDW modulation develops. These transverse displacements, along with electron pinning from the iodine deficiency, help explain why (TaSe4)2I behaves as an electronic semiconductor at temperatures above and below T_CDW, despite a metallic band structure calculated from density functional theory of the ideal structure."],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2142/122172"],"dc:language":["en","eng"],"dc:rights":["Copyright 2023 Jacob Andrew Christensen"],"dc:subject":["Charge Density Waves","Peierls Transition","Topological Materials","Pump-probe Spectroscopy","Scanning Transmission Electron Microscopy","X-ray Diffraction","Chiral Symmetry","Lattice Modeling"],"dc:title":["Disorder and diffuse scattering in single-chirality (TaSe4)2I crystals"],"dc:type":["text"],"thesis:degree_discipline":["Materials Science & Engr"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["M.S."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:00Z"}