{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/24247"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/24247","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"The current-phase relation of graphene-based Josephson junctions","abstract":"The current-phase relation (CPR) of a Josephson junction reveals valuable information about the microscopic processes and symmetries that influence the supercurrent. For the work described in this thesis, we have studied the CPR of graphene-based Jospehson junctions, inspired by previous theoretical predictions of a departure from the usual sinusoidal functionality, or skewness, of the CPR. The experimental data was obtained by incorporating the junction into an rf SQUID geometry coupled to a dc SQUID magnetometer, a technique usually referred to as phase-sensitive SQUID interferometry, which allows for the direct measurement of the phase difference across the junction. While some of the predictions from theory - like the departure of the CPR from sinusoidal behavior, its symmetry with carrier nature and the de-skewing with increasing temperature - were qualitatively observed, others were inconsistent with the experimental data. Perhaps the most important disparity was that of the functionality of the skewing, which we found to vary linearly with critical current (Ic ), independent of the carrier density/temperature combination used to attain Ic. It is worth mentioning that our measurements have prompted renewed theoretical interest in this system, culminating in the modification of the original model to include the effects of temperature, and a recent publication venturing an explanation for the observed linearity of the CPR skewness with Ic.","abstract_html":"The current-phase relation (CPR) of a Josephson junction reveals valuable information about the microscopic processes and symmetries that influence the supercurrent. For the work described in this thesis, we have studied the CPR of graphene-based Jospehson junctions, inspired by previous theoretical predictions of a departure from the usual sinusoidal functionality, or skewness, of the CPR. The experimental data was obtained by incorporating the junction into an rf SQUID geometry coupled to a dc SQUID magnetometer, a technique usually referred to as phase-sensitive SQUID interferometry, which allows for the direct measurement of the phase difference across the junction. While some of the predictions from theory - like the departure of the CPR from sinusoidal behavior, its symmetry with carrier nature and the de-skewing with increasing temperature - were qualitatively observed, others were inconsistent with the experimental data. Perhaps the most important disparity was that of the functionality of the skewing, which we found to vary linearly with critical current (Ic ), independent of the carrier density/temperature combination used to attain Ic. It is worth mentioning that our measurements have prompted renewed theoretical interest in this system, culminating in the modification of the original model to include the effects of temperature, and a recent publication venturing an explanation for the observed linearity of the CPR skewness with Ic.","abstract_has_math":false,"creators":["Chialvo, Cesar E."],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Mason, Nadya","Eckstein, James N.","Stone, Michael","Gollin, George D."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-25T15:06:37Z","date_published":"2011-05-25T15:06:37Z","updated_at":"2026-07-22T22:25:24Z","subjects":["Graphene","current-phase relation (CPR)","Josephson junctions","nano-fabrication","micro-fabrication"],"languages":["en"],"rights":["Copyright 2011 Cesar E. Chialvo"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/24247","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Mason, Nadya","Eckstein, James N.","Stone, Michael","Gollin, George D."]},{"key":"dc:creator","label":"Author","values":["Chialvo, Cesar E."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-25T15:06:37Z","2011-05"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"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":["Graphene","current-phase relation (CPR)","Josephson junctions","nano-fabrication","micro-fabrication"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2011 Cesar E. 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While some of the predictions from theory - like the departure of the CPR from sinusoidal behavior, its symmetry with carrier nature and the de-skewing with increasing temperature - were qualitatively observed, others were inconsistent with the experimental data. Perhaps the most important disparity was that of the functionality of the skewing, which we found to vary linearly with critical current (Ic ), independent of the carrier density/temperature combination used to attain Ic. It is worth mentioning that our measurements have prompted renewed theoretical interest in this system, culminating in the modification of the original model to include the effects of temperature, and a recent publication venturing an explanation for the observed linearity of the CPR skewness with Ic.","Item withdrawn by Alexis Thompson (athmpsn1@illinois.edu) on 2011-04-20T18:14:33Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 1 Chialvo_Cesar.pdf: 44703470 bytes, checksum: 1b66ec7f1187889b7a346a36f8229870 (MD5)","Made available in DSpace on 2011-05-25T15:06:37Z (GMT). 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The experimental data was obtained by incorporating the junction into an rf SQUID geometry coupled to a dc SQUID magnetometer, a technique usually referred to as phase-sensitive SQUID interferometry, which allows for the direct measurement of the phase difference across the junction. While some of the predictions from theory - like the departure of the CPR from sinusoidal behavior, its symmetry with carrier nature and the de-skewing with increasing temperature - were qualitatively observed, others were inconsistent with the experimental data. Perhaps the most important disparity was that of the functionality of the skewing, which we found to vary linearly with critical current (Ic ), independent of the carrier density/temperature combination used to attain Ic. It is worth mentioning that our measurements have prompted renewed theoretical interest in this system, culminating in the modification of the original model to include the effects of temperature, and a recent publication venturing an explanation for the observed linearity of the CPR skewness with Ic.","Item withdrawn by Alexis Thompson (athmpsn1@illinois.edu) on 2011-04-20T18:14:33Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 1 Chialvo_Cesar.pdf: 44703470 bytes, checksum: 1b66ec7f1187889b7a346a36f8229870 (MD5)","Made available in DSpace on 2011-05-25T15:06:37Z (GMT). No. of bitstreams: 2 Chialvo_Cesar.pdf: 44698566 bytes, checksum: d5d0aeac538b104c579ea59cfb5be7ff (MD5) license.txt: 4063 bytes, checksum: 4eddde6df7f36fbb5b673e2046cba6eb (MD5)"],"dc:identifier":["http://hdl.handle.net/2142/24247"],"dc:language":["en"],"dc:rights":["Copyright 2011 Cesar E. Chialvo"],"dc:subject":["Graphene","current-phase relation (CPR)","Josephson junctions","nano-fabrication","micro-fabrication"],"dc:title":["The current-phase relation of graphene-based Josephson junctions"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:24Z"}