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Showing 1 to 20 of 184 for “"Order Parameter"”.
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Superconducting order parameter domains in Sr2RuO4 probed by Josephson interferometry
There is evidence for degenerate chiral order parameters of px±ipy symmetry in the superconducting ruthenate Sr2RuO4 which can lead to the presence of chiral order parameter domains in the material. We study bi-metallic Josephson junctions made of Sr2RuO4 and a conventional superconductor. Their …
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On an Order-Parameter Model of Solid-Solid Phase Transitions
… that includes thermo-elastic effects and an order parameter. The model is derived as a special case of the Gurtin-Fried model posed in one space dimension with a symmetric triple-well free energy in which the relative heights of the wells vary with temperature. We examine the temperature …
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Superconducting Order Parameter Domains in Strontium Ruthenate Probed by Josephson Interferometry
There is evidence for degenerate chiral order parameters of px +/- ipy symmetry in the superconducting ruthenate Sr 2RuO4 which can lead to the presence of chiral order parameter domains in the material. We study bi-metallic Josephson junctions made of Sr2RuO4 and a conventional superconductor. …
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Determining the superconducting order parameter of UPt3 with Josephson junction interferometry
Made available in DSpace on 2010-05-14T20:51:19Z (GMT). No. of bitstreams: 2 Strand_Joel.pdf: 3215583 bytes, checksum: 56bc27939f1df7406b5bd380bfc02090 (MD5) license.txt: 4060 bytes, checksum: 7daff777161209135fcbaaaff684d71b (MD5)
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Probing the superconducting order parameter of Iron-based superconductors through the Josephson effect
… to probe the symmetry of the superconducting order parameter of Co-doped Ba(FeAs)2 crystals (Ba122). This measurements were carried out to test the validity of the s± model, which predicts the pairing in the multiband Ba122 compounds being mediated by the exchange of spin excitations, with the …
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Experimental determination of the symmetry of the superconducting pairing state in yttrium barium copper oxide
… anisotropy of the phase of the superconducting order parameter, we can experimentally determine the symmetry of the superconducting pairing state in YBCO and distinguish between the leading candidate states that have been proposed. We find that the superconducting order parameter in YBCO changes …
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Josephson Interferometry Measurements in High-T(c) Grain Boundary Junctions
… states lead to a suppression of the d-wave order parameter and formation of a subdominant pairing phase with a complex order parameter characterized by broken time-reversal symmetry. A similar phenomenon is predicted to occur in the bulk film near magnetic impurities. Calculations …
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Josephson Interferometry Measurements in High-Tc Grain Boundary Junctions
… states lead to a suppression of the d-wave order parameter and formation of a subdominant pairing phase with a complex order parameter characterized by broken time-reversal symmetry. A similar phenomenon is predicted to occur in the bulk film near magnetic impurities. Calculations …
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Conductivity and Interferometry Experiments on YBCO/lead Ramp-Edge Josephson Junctions
In this thesis, we study the details of the order parameter symmetry in arbitrary directions of the high-temperature cuprate superconductor YBa 2Cu3O7-y (YBCO) using YBCO/Pb ramp-edge Josephson junctions with lithographically defined corner and straight-edge geometries. Measurements of the critical …
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Switching Current Distributions of Superconducting Nanowires: Evidence of Quantum Phase Slip Events
… events that carry the superconducting order-parameter field between distinct current carrying states. Owing to these phase slips low-dimensional superconductors acquire electrical resistance. In quasi-one-dimensional nanowires it is well known that at higher temperatures phase slips …
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Probing the chiral domain structure and dynamics in SR2RUO4 with nanoscale Josephson junctions
… superconducting state is unconventional with an order parameter symmetry of px ipy. Measurements using Josephson Interferometry have shown evidence for chiral order parameter domains on the order of 1 m in size. To further search for signatures of these domains we have fabricated Josephson …
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The statistical mechanics of continuous random networks
… such networks vary across the sample. A natural order parameter, resulting from a statistical-mechanical approach, captures information concerning this heterogeneity via a certain joint probability distribution. This joint probability distribution describes the variations in the positional and …
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Many-body entanglement : topological orders, tensor networks and superconductivity
… entanglements. We try to establish a non-local "order parameter" description of different patterns of many-body entanglement, which are also named topological orders. In 2+ 1D, we show that this could be achieved by calculating the non-Abelian geometric phase (S, T)-matrices from the fixed-point …
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Supercurrents in Restricted Geometries and Driven by Time-Dependent Electric Fields
… electric field. In a preparatory section the order-parameter profile and the density of states were calculated in equilibrium. We showed that the density of states in the normal metal is unaltered if the impurity self-energies are not taken into account while the coherence in the …
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Approach to equilibrium in systems with continuous symmetries
… simulations of a simple model with non-conserved order parameter and the symmetry of a planar ferromagnet. A transient behavior is observed at early times in two dimensions. Finite-size scaling of the scattering function is demonstrated and it is shown that dynamical scaling is satisfied not only …
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Investigation of Iron-Based and Topological Superconductors via Point-Contact Spectroscopy
… which confirm a lack of nodes in the order parameter and the presence of a gap of magnitude 3 meV. Conductivity spectra were also measured for the half-Heusler materials YPtBi and LuPdBi using the soft point contact method. I argue that the repeated observation of a single peak in …
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Heat capacity measurements of yttrium barium(2)copper(3)oxygen(7-delta) near T(c): Fluctuation effects in a bulk superconductor
… heat capacity data are analyzed both as a lowest-order correction to mean-field BCS theory (the Gaussian approximation) and in terms of true critical behavior. The analysis shows that the data are best described within the Gaussian approximation as three-dimensional fluctuations of a two-component …
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Investigation of half-quantized fluxoid states in Sr2RuO4 mesoscopic superconducting rings
… angular momentum and form domain structure with order parameter that corresponds to . For micron-size samples, only a few number of domains would exist and signatures of domain walls and edge currents are expected to be measurable with current sensitivity. From the measurements of fluctuations of …
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Effective action approach to quantum phase transitions in bosonic lattices
… the tunneling and the source term. From here, an order parameter field is introduced, and the underlying effective action is derived via a Legendre transformation. After determining the Ginzburg-Landau expansion of the effective action to first order in the tunneling term. expressions for the Mott …
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