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oai:www.ideals.illinois.edu:2142/24247 2023-07-10 col_2142_5131 col_2142_8859 com_2142_5130 com_2142_8858 com_2142_234

Mason, Nadya Eckstein, James N. Mason, Nadya Stone, Michael Gollin, George D. Chialvo, Cesar E. 2011-05-25T15:06:37Z 2011-05-25T15:06:37Z 2011-05-25T15:06:37Z 2011-05 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. Item withdrawn by Alexis Thompson (athmpsn1@illinois.edu) on 2011-04-20T18:14:33Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of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) http://hdl.handle.net/2142/24247 en Copyright 2011 Cesar E. Chialvo Graphene current-phase relation (CPR) Josephson junctions nano-fabrication micro-fabrication The current-phase relation of graphene-based Josephson junctions Physics 1244 Physics 0240 University of Illinois at Urbana-Champaign Dissertation Ph.D. PHD:Physics -UIUC 10KS0240PHD