Topic
High-temperature superconductivity
About: High-temperature superconductivity is a research topic. Over the lifetime, 7263 publications have been published within this topic receiving 175377 citations. The topic is also known as: high-temperature superconductivity.
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43 citations
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TL;DR: In this paper, the spin fluctuations and the symmetries of the superconducting gaps for different iron-based superconductors are studied. And the authors argue that the spin fluctuation is the common origin of superconductivity.
Abstract: In this article, we review the recent theoretical works on the spin fluctuations and superconductivity in iron-based superconductors. Using the fluctuation exchange approximation and multi-orbital tight-binding models, we study the characteristics of the spin fluctuations and the symmetries of the superconducting gaps for different iron-based superconductors. We explore the systems with both electron-like and hole-like Fermi surfaces (FS) and the systems with only the electron-like FS. We argue that the spin-fluctuation theories are successful in explaining at least the essential part of the problems, indicating that the spin fluctuation is the common origin of superconductivity in iron-based superconductors.
43 citations
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TL;DR: Very severe upper bounds for the total magnetic intensity could be established, making magnetic couplings as a source for superconductivity in YBa2Cu3O7 highly unlikely as mentioned in this paper, which makes magnetic coupling in superconductor highly unlikely.
Abstract: To decide whether magnetic fluctuations are present in the high-temperature superconductor YBa2Cu3O7, we carried out a neutron scattering experiment, using 3-dimensional polarization analysis at temperatures between 70 K and 300 K. The total magnetic intensity within energy windows - Ω < ω < Ω for Ω = 12 meV and 25 meV is vanishingly small. Very severe upper bounds for the total magnetic intensity could be established, making magnetic couplings as a source for superconductivity in YBa2Cu3O7 highly unlikely.
43 citations
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TL;DR: In this paper, the magnetic relaxation rate was calculated for the vortex-glass or collective-creep model and the thermal activated model considering backward hopping, and it was found that the former models were in good agreement with the experiment at relatively low temperature regions, while the latter were at higher temperatures near Tc.
43 citations
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TL;DR: In this article, it was shown that the low-energy physics responsible for the high-T-c superconductivity of iron-based superconductors is essentially governed by an effective two-orbital Hamiltonian near half filling.
Abstract: Although iron-based superconductors are multiorbital systems with complicated band structures, we demonstrate that the low-energy physics which is responsible for their high-T-c superconductivity is essentially governed by an effective two-orbital Hamiltonian near half filling. This underlying electronic structure is protected by the S-4 symmetry. With repulsive or strong next-nearest-neighbor antiferromagnetic exchange interactions, the model results in a robust A(1g) s-wave pairing which can be mapped exactly to the d-wave pairing observed in cuprates. The classification of the superconducting (SC) states according to the S4 symmetry leads to a natural prediction of the existence of two different phases, named the A and B phases. In the B phase, the superconducting order has an overall sign change along the c axis between the top and bottom As (or Se) planes in a single Fe-As (or Fe-Se) trilayer structure, the common building block of iron-based superconductors. The sign change is analogous to the sign change in the d-wave superconducting state of cuprates upon 90 degrees rotation. Our derivation provides a unified understanding of iron pnictides and iron chalcogenides, and suggests that cuprates and iron-based superconductors share an identical high-T-c superconducting mechanism.
43 citations