Fractional flux plateau in magnetization curve of multicomponent superconductor loop

Huang, Zhao Hui; Hu, Xiao

doi:10.1103/physrevb.92.214516

Cited by 7 publications

(6 citation statements)

References 58 publications

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“…It is interesting to note that a similar experimental setup was proposed with the aim to detect a fractional flux plateau in the magnetization curve of a superconducting loop that is topologically the same as the one considered here 43 . These authors investigate numerically metastable phase kinks protected by a large energy barrier within a GL functional adopting certain special parameter values.…”

Section: Btrs and Trs Superconductors On A Cylinder And In Magnetic F...mentioning

confidence: 96%

Anomalous diamagnetic response in multiband superconductors with broken time-reversal symmetry

et al. 2017

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Within a Ginzburg-Landau formalism we establish analytically the necessary and sufficient conditions to realize a doubly degenerate superconducting ground state with broken time-reversal symmetry (BTRS) in a multi-band superconductor. Using these results we analyze the ground state of a three band superconductor in the cylindrical geometry in an external magnetic field. We show that depending on the interband coupling constants, a magnetic flux can induce current density jumps in such superconducting geometries that are related to adiabatic or non-adiabatic transitions from BTRS to time-reversal symmetric states and vice versa. This unusual current induced magnetic flux response can in principle be used experimentally to detect superconducting BTRS ground states as well as corresponding metastable excited states. arXiv:1707.02345v1 [cond-mat.supr-con]

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Section: Btrs and Trs Superconductors On A Cylinder And In Magnetic F...mentioning

confidence: 96%

Anomalous diamagnetic response in multiband superconductors with broken time-reversal symmetry

et al. 2017

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“…In Refs. [58,59,59], Josephson junctions between chiral and regular superconductors were considered: the asymmetric critical currents, subharmonic Shapiro steps, symmetric Fraunhofer patterns [58], and the fractional flux and its plateau in magnetization curve [59,60] are studied by using Bogoliubov-de Gennes and the time-dependent Ginzburg-Landau equation. Also, in Ref.…”

Section: Summary and Discussionmentioning

confidence: 99%

Field theoretical model of multilayered Josephson junction and dynamics of Josephson vortices

Fujimori¹,

Iida²,

Nitta³

2016

Phys. Rev. B

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Multilayered Josephson junctions are modeled in the context of a field theory, and dynamics of Josephson vortices trapped inside insulators are studied. Starting from a theory consisting of complex and real scalar fields coupled to a U(1) gauge field which admit parallel N − 1 domain-wall solutions, Josephson couplings are introduced weakly between the complex scalar fields. The N − 1 domain walls behave as insulators separating N superconductors, where one of the complex scalar fields has a gap. We construct the effective Lagrangian on the domain walls, which reduces to a coupled sine-Gordon model for well-separated walls and contains more interactions for walls at short distance. We then construct sine-Gordon solitons emerging in an effective theory in which we identify Josephson vortices carrying singly quantized magnetic fluxes. When two neighboring superconductors tend to have the same phase, the ground state does not change with the positions of domain walls (the width of superconductors). On the other hand, when two neighboring superconductors tend to have π -phase differences, the ground state has a phase transition depending on the positions of domain walls; when the two walls are close to each other (one superconductor is thin), frustration occurs because of the coupling between the two superconductors besides the thin superconductor. Focusing on the case of three superconductors separated by two insulators, we find for the former case that the interaction between two Josephson vortices on different insulators changes its nature, i.e., attractive or repulsive, depending on the positions of the domain walls. In the latter case, there emerges fractional Josephson vortices when two degenerate ground states appear due to spontaneous charge-symmetry breaking, and the number of the Josephson vortices varies with the position of the domain walls. Our predictions should be verified in multilayered Josephson junctions.

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“…We would like to note that an HQV fluxoid state can also be formed from chiral domains and domain walls expected in a chiral p-wave, Γ − 5 state [16]. It was predicted [16,54] that the formation of the domain walls in the cylinder will lead to the formation of a fractional quantum vortex (including HQV) in general. Experimentally, the formation of chiral domains in Sr 2 RuO 4 was explored previously, e.g., in a Josephson junction study of time-reversal symmetry breaking in Sr 2 RuO 4 [55].…”

Section: Pairing Symmetry In Sr2ruo4mentioning

confidence: 94%

Magnetoresistance oscillation study of the half-quantum vortex in doubly connected mesoscopic superconducting cylinders of Sr2RuO4

Cai,

Zakrzewski,

Ying

et al. 2020

Preprint

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The observation of the highly unusual half-quantum vortex (HQV) in a single crystalline superconductor excludes unequivocally the spin-singlet symmetry of the superconducting order parameter. HQVs were observed previously in mesoscopic samples of Sr2RuO4 in cantilever torque magnetometry measurements, thus providing direct evidence for spin-triplet pairing in the material. In addition, it raised important questions on HQV, including its stability and dynamics. These issues have remained largely unexplored, in particular, experimentally. We report in this paper the detection of HQVs in mesoscopic, doubly connected cylinders of single-crystalline Sr2RuO4 of a mesoscopic size and the examination of the effect of the in-plane magnetic field needed for the observation of the HQV by magnetoresistance (MR) oscillations measurements. Several distinct features found in our data, especially a dip and secondary peaks in the MR oscillations seen only in the presence of a sufficiently large in-plane magnetic field as well as a large measurement current, are linked to the formation of the HQV fluxoid state in the sample and crossing of an Abrikosov HQV through the sample. The conclusion is drawn from the analysis of our data using a model of thermally activated vortex crossing overcoming a free-energy barrier which is modulated by the applied magnetic flux enclosed in the cylinder as well as the measurement current. Evidence for the trapping of an HQV fluxoid state in the sample was also found. Our observation of the HQV in mesoscopic Sr2RuO4 provided not only additional evidence for spin-triplet superconductivity in Sr2RuO4 but also insights into the physics of HQV, including its spontaneous spin polarization, stability, and dynamics. Our study also revealed a possible effect of the measurement current on the magnitude of the spontaneous spin polarization associated with the HQV.

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Fractional flux plateau in magnetization curve of multicomponent superconductor loop

Cited by 7 publications

References 58 publications

Anomalous diamagnetic response in multiband superconductors with broken time-reversal symmetry

Anomalous diamagnetic response in multiband superconductors with broken time-reversal symmetry

Field theoretical model of multilayered Josephson junction and dynamics of Josephson vortices

Magnetoresistance oscillation study of the half-quantum vortex in doubly connected mesoscopic superconducting cylinders of Sr2RuO4

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