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تسجيل مستخدم جديدParticle-hole symmetry reveals failed superconductivity in the metallic phase of two-dimensional superconducting films
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Electrons confined to two dimensions display an unexpected diversity of behaviors as they are cooled to absolute zero. Noninteracting electrons are predicted to eventually localize into an insulating ground state, and it has long been supposed that electron correlations stabilize only one other phase: superconductivity. However, many two-dimensional (2D) superconducting materials have shown surprising evidence for metallic behavior, where the electrical resistivity saturates in the zero-temperature limit, the nature of this unexpected metallic state remains under intense scrutiny. We report electrical transport properties for two disordered 2D superconductors, indium oxide and tantalum nitride, and observe a magnetic field-tuned transition from a true superconductor to a metallic phase with saturated resistivity. This metallic phase is characterized by a vanishing Hall resistivity, suggesting that it retains particle-hole symmetry from the disrupted superconducting state.
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tex exists in the broad range of parameters. When the coherence length decreases the topological phase transition to the phase with the same total vorticity and a reduced symmetry takes place. The giant vortex with the vorticity $m=3$ is found to be unstable for any field, $xi /a$ and $kappa_{eff}ge 0.1$. Reduction of $ kappa _{eff}$ does not make the phase with antivortex more stable contrary to the case of the cylindric sample of the type I superconductor.
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