We characterize the mechanisms of vortex pinning in a superfluid thin film described by the two-dimensional Gross-Pitaevskii equation. We consider a vortex "scattering experiment" whereby a single vortex in a superfluid flow interacts with a circular, uniform pinning potential. By an analogy with linear dielectrics, we develop an analytical hydrodynamic approximation that predicts vortex trajectories, the vortex fixed point and the unpinning velocity. We then solve the Gross-Pitaevskii equation to validate this model, and build a phase portrait of vortex pinning. We identify two different dynamical pinning mechanisms marked by distinctive phonon emission signatures: one enabled by acoustic radiation and another mediated by vortex dipoles nucleated within the pin. Relative to obstacle size, we find that pinning potentials on the order of the healing length are more effective for vortex capture. Our results could be useful in mitigating the negative effects of drag due to vortices in superfluid channels, in analogy to maximizing supercurrents in type-II superconductors.
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http://dx.doi.org/10.1103/PhysRevLett.127.255302 | DOI Listing |
Nanoscale
January 2025
Department of Materials Science and Engineering, Kyushu Institute of Technology, 1-1 Sensui-cho, Tobata-ku, Kitakyushu 804-8550, Japan.
Self-organization realizes various nanostructures to control material properties such as superconducting vortex pinning and thermal conductivity. However, the self-organization of nucleation and growth is constrained by the growth geometric symmetry. To realize highly controlled three-dimensional nanostructures by self-organization, nanostructure formation that breaks the growth geometric symmetry thermodynamically and kinetically, such as tilted or in-plane aligned nanostructures, is a challenging issue.
View Article and Find Full Text PDFJ Phys Condens Matter
December 2024
School of Physical Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
Superconductors based on transition metal dichalcogenides are of substantial current relevance towards the material realization of topological superconductivity. Here, we report a detailed study on the synthesis and characterization of single crystals of 2H-TaSeS. A superconducting transition is confirmed at4.
View Article and Find Full Text PDFJ Phys Condens Matter
November 2024
Institute of Physics and Technology, Ufa University of Science and Technology, Ufa 450076, Russia.
In this paper, the stabilization conditions, structure, and properties of possible vortex-like inhomogeneities, including k-skyrmions= 0, 1, 2, 3, 4, in a uniaxial multilayer disk with a columnar defect in the center are investigated based on micromagnetic modeling. Their stability diagrams depending on the Dzyaloshinskii-Moriya interaction, the magnitude of magnetic anisotropy and the defect parameters are determined. New types of vortex-like inhomogeneities that can arise in such samples are found.
View Article and Find Full Text PDFNanomaterials (Basel)
September 2024
Department of Basic and Applied Sciences, A'Sharqiyah University, P.O. Box 42, Ibra 400, Oman.
In this study, we investigate the thermal pinning and depinning behaviors of vortex domain walls (VDWs) in constricted magnetic nanowires, with a focus on potential applications in storage memory nanodevices. Using micromagnetic simulations and spin transfer torque, we examine the impacts of device temperature on VDW transformation into a transverse domain wall (TDW), mobility, and thermal strength pinning at the constricted area. We explore how thermal fluctuations influence the stability and mobility of domain walls within stepped nanowires.
View Article and Find Full Text PDFNanoscale
October 2024
School of Physics and Astronomy, Cardiff University, Cardiff, CF24 3AA, UK.
The study of 3D magnetic nanostructures has uncovered rich phenomena including the stabilization of topological spin textures using nanoscale curvature, controlled spin-wave emission, and novel ground states enabled by collective frustrated interactions. From a technological perspective, 3D nanostructures offer routes to ultrahigh density data storage, massive interconnectivity within neuromorphic devices, as well as mechanical induction of stem cell differentiation. However, the fabrication of 3D nanomagnetic systems with feature sizes down to 10 nm poses a significant challenge.
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