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| viXra.org > Condensed Matter > 2410 |
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[3] viXra:2410.0146 [pdf] submitted on 2024-10-23 13:29:46
Authors: Xiuqing Huang
Comments: 14 Pages.
Despite decades of research, the origin of high-temperature superconductivity is still unclear, and its microscopic mechanism remains a subject of intense debate. The intrinsic Mott insulating properties of copper oxide parent compounds and the experimentally observed charge-ordered phases in real space suggest that high-temperature superconductivity may stem from localized electrons rather than itinerant electrons. In this work, we propose a unified microscopic mechanism where confined electrons within polyhedral quantum wells represent the Mott ground state, and symmetry-breaking of electron-hole pairs acts as the superconducting mechanism. A single parameter formula for the critical temperature (Tc) of unconventional superconductors is developed, allowing accurate determination of Tc based on lattice constants. The approach elucidates relationships between various charge-order phases and doping concentration, explores Fermi surface structures, investigates spin resonance peaks and parities, and examines pressure-induced dual superconducting phase transitions - all consistent with experimental observations. It is also estimated that the highest Tc of the newly discovered nickel-based superconductor will not exceed 100 K. This work offers critical insights into unconventional superconductivity’s fundamental mechanisms while introducing a new paradigm to reveal more intrinsic connections between superconductivity, conductivity, and magnetism.
Category: Condensed Matter
[2] viXra:2410.0014 [pdf] submitted on 2024-10-03 08:45:48
Authors: Marcello Colozzo
Comments: 6 Pages.
The self-compatible Hartree method is used in atomic physics to determine the energy levels of many-electron atoms. In this work we extend this procedure to electrons moving in the Coulomb field of a distribution of positive ions in a Bravais lattice.
Category: Condensed Matter
[1] viXra:2410.0003 [pdf] submitted on 2024-10-02 20:52:57
Authors: Peter Krampl
Comments: 23 Pages.
An interesting aspect of this thesis should be mentioned right at the beginning. It was shown that the higher harmonics generated by non-centrosymmetric bonded electrons can take on properties of negative index systems. By controlling the nonlinearity, tailor-made optical metamaterials with a defined negative refractive index are possible. This becomes interesting in the context of the fact that matter waves with a refractive index of exactly minus one form the perfect microscope. A suitable set of new characteristic optical response tensors, which are no longer Lorentzartig in view of the newly gained knowledge, were derived for non-centrosymmetric media and their importance for the various nonlinear orbital response functions was shown and discussed. The nonlinear resonant denominator function can α be rewritten depending on the strength of the nonlinearity, where noncentrosymmetric matter scales in the nonlinear mode with negative SKEWNESS and centrosymmetric matter, as well as the transition bulk / surface with positive SKEWNESS, and the harmonics can be classified depending on the introduced parameters p and q. The nonlinearity in the denominator function takes into account the occurring skewness and the destabilization of increasing nonlinear amplitudes, in contrast to the current literature (e.g. Boyd), in which α occurs only as a proportionality factor, in which the amplitude is linearly and directly influenced and no destabilization of the amplitudes in the nonlinear regime is described. Due to the symmetry of non-centrosymmetric matter, no longitudinal modes are capable of propagation. The nonlinear dielectric spectral response function has singularities for non-dissipative matter at any transition frequency. The analysis taking into account dissipative effects showed an elimination of these singularities. You get curves with negative skewness. In the identified regions of negative dielectric function, a real refractive index of less than 1 exists. The refractive index is imaginary there, which is usually characteristic of surface plasmons. In this area, it is in principle possible to produce optical metamaterials by setting suitable nonlinearity. In the linear case, the spectral function has a zero position, so that longitudinal modes can also propagate for this. Variation of nonlinearity causes a very large positive or negative skew depending on the sign and shows frequency conversion. (Truncated by viXra Admin to < 400 words)
Category: Condensed Matter
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