Phonon self-energy effects in the superconducting energy gap ofMgB2point-contact spectra

The sharp low energy kink (LEK) in quasiparticle (qp) spectra well below the superconducting energy gap observed in the angle-resolved photo-emission spectroscopy (ARPES) of the Bi-cuprates may be understood in terms of the forward scattering impurities located off the Cu–O planes. The relevance of the idea has been established by comparing the calculated normal self-energy from the off-plane impurity effects and the extracted one from the self-energy analysis of [Formula: see text] (Bi2212) ARPES data in Hong et al. [Phys. Rev. Lett. 113, 057001 (2014)]. In addition to the explanation of the LEK, this is a necessary step to analyze ARPES data, to reveal the spectrum of fluctuations promoting superconductivity. We also present the extracted anomalous self-energy from the self-energy analysis, which is its first experimental determination as far as we are aware of. The extracted anomalous self-energy and its implications are discussed in comparison with the calculated impurity self-energy term.

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Theory on Neutrino Self-Energy and Neutrino Oscillation with Consideration of Superconducting Energy Gap and Fermi’s Golden Rule

10.20944/preprints201910.0080.v1 ◽

2019 ◽

Author(s):

Shinichi Ishiguri

Keyword(s):

Neutrino Oscillation ◽

Energy Gap ◽

Transition Probabilities ◽

Golden Rule ◽

Neutrino Energy ◽

Einstein Condensation ◽

Self Energy ◽

Superconducting Energy Gap ◽

Bose Einstein ◽

Many Body Interactions

We herein described an investigation of a theory, which describes the energies of neutrinos and the source of neutrino oscillations. A series of experiments were conducted to show evidences of the existence a neutrino mass. We also applied theories to explain the reason for the extremely small energy of a neutrino, mainly by employing a vacuum-derived superconducting energy gap from the Bardeen–Cooper–Schrieffer ground state. Moreover, we succeeded in obtaining the transition probabilities of neutrinos’ flavors (i.e., in terms of neutrino oscillation). We focused on the fact that up- and down-quantized space pairs combine by the Lorentz forces, undertake Bose-Einstein condensation, and then create a superconducting energy gap at the energy level of the vacuum with quantum mechanics fluctuation. Eventually, the superconducting energy gap vanishes to form a real body of the neutrino. Furthermore, assuming that the speed of the neutrino is near the speed of light and exhibits Planck’s blackbody emissions, we derived many-body interactions of neutrinos and applied them in Fermi’s golden rule. As a result, the neutrino energy we calculated agreed well within the realms of the experimental results. The calculated transition probabilities of neutrino’s flavor also explain the experiment results very well.

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Superconducting energy gap from break-junction tunneling spectroscopy in the ternary silicide CaAlSi

Physical Review B ◽

10.1103/physrevb.76.104508 ◽

2007 ◽

Vol 76 (10) ◽

Cited By ~ 6

Author(s):

S. Kuroiwa ◽

T. Takasaki ◽

T. Ekino ◽

J. Akimitsu

Keyword(s):

Energy Gap ◽

Tunneling Spectroscopy ◽

Break Junction ◽

Superconducting Energy Gap ◽

Ternary Silicide

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High Tc Oxide Superconductors

MRS Bulletin ◽

10.1557/s0883769400059479 ◽

1990 ◽

Vol 15 (6) ◽

pp. 31-33

Author(s):

M. Brian Maple

Keyword(s):

Physical Properties ◽

Energy Gap ◽

Vortex State ◽

Oxide Superconductors ◽

High Tc ◽

Superconducting Energy Gap ◽

Consistent Picture ◽

Novel Processing ◽

Processing Techniques

This issue of the MRS BULLETIN is devoted to high Tc superconductivity. It is the sequel to a previous series of articles on the same subject which appeared in the MRS BULLETIN in January 1989. While the articles in the January 1989 issue emphasized the families of high Tc superconducting oxides known at that rime, as well as novel processing techniques and thin films, the papers in this issue focus on the physical properties of high Tc oxide superconductors.The quality of polycrystalline and single-crystal bulk and thin-film materials has improved to the point where researchers can now make reliable measurements of many physical properties representative of the intrinsic behavior of these materials. As a result, a broad spectrum of important issues such as the nature of the electronic structure, the type of superconducting electron pairing, the magnitude and temperature dependence of the superconducting energy gap, the behavior of fluxoids in the vortex state, etc., can be addressed meaningfully. Presently emerging is a consistent picture of the physical properties of the high Tc oxides, which will form the foundation to eventually developing an appropriate theory for the normal and superconducting states of these remarkable materials.

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Measurement of the Superconducting Energy Gap and Fermi Velocity in Single-Crystal Lead Films by Electron Tunneling

Physical Review B ◽

10.1103/physrevb.4.1523 ◽

1971 ◽

Vol 4 (5) ◽

pp. 1523-1530 ◽

Cited By ~ 53

Author(s):

G. I. Lykken ◽

A. L. Geiger ◽

K. S. Dy ◽

E. N. Mitchell

Keyword(s):

Single Crystal ◽

Energy Gap ◽

Electron Tunneling ◽

Fermi Velocity ◽

Superconducting Energy Gap ◽

Lead Films

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Temperature dependence of the superconducting energy gap within the Eliashberg theory involving the energy-varying electronic density of states

Physica C Superconductivity ◽

10.1016/0921-4534(95)00227-8 ◽

1995 ◽

Vol 248 (1-2) ◽

pp. 83-91 ◽

Cited By ~ 6

Author(s):

Yasushi Yokoya ◽

Yoshiko Oi Nakamura

Keyword(s):

Temperature Dependence ◽

Density Of States ◽

Energy Gap ◽

Electronic Density ◽

Eliashberg Theory ◽

Electronic Density Of States ◽

Superconducting Energy Gap

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Higher derivatives driven symmetry breaking in holographic superconductors

The European Physical Journal C ◽

10.1140/epjc/s10052-020-7670-y ◽

2020 ◽

Vol 80 (2) ◽

Author(s):

Hai-Li Li ◽

Guoyang Fu ◽

Yan Liu ◽

Jian-Pin Wu ◽

Xin Zhang

Keyword(s):

High Temperature Superconductor ◽

Energy Gap ◽

Coupling Term ◽

Holographic Superconductor ◽

Complex Scalar ◽

Holographic Superconductors ◽

Higher Derivative ◽

Superconducting Energy Gap ◽

Higher Derivatives ◽

Complex Scalar Field

Abstract In this paper, we construct a novel holographic superconductor from higher derivative (HD) gravity involving a coupling between the complex scalar field and the Weyl tensor. This HD coupling term provides a near horizon effective mass squared, which can violates IR Breitenlohner–Freedman (BF) bound by tuning the HD coupling and induces the instability of black brane such that the superconducting phase transition happens. We also study the properties of the condensation and the conductivity in the probe limit. We find that a wider extension of the superconducting energy gap ranging from 4.6 to 10.5 may provide a novel platform to model and interpret the phenomena in the real materials of high temperature superconductor.

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Momentum-resolved superconducting energy gaps of Sr2RuO4 from quasiparticle interference imaging

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1916463117 ◽

2020 ◽

Vol 117 (10) ◽

pp. 5222-5227 ◽

Cited By ~ 9

Author(s):

Rahul Sharma ◽

Stephen D. Edkins ◽

Zhenyu Wang ◽

Andrey Kostin ◽

Chanchal Sow ◽

...

Keyword(s):

Knight Shift ◽

Energy Gap ◽

Space Structure ◽

Superconducting Order Parameter ◽

Temperature Dependent ◽

High Precision Measurement ◽

Quasiparticle Interference ◽

Energy Gaps ◽

Superconducting Energy Gap ◽

Intense Research

Sr2RuO4 has long been the focus of intense research interest because of conjectures that it is a correlated topological superconductor. It is the momentum space (k-space) structure of the superconducting energy gap Δi(k) on each band i that encodes its unknown superconducting order parameter. However, because the energy scales are so low, it has never been possible to directly measure the Δi(k) of Sr2RuO4. Here, we implement Bogoliubov quasiparticle interference (BQPI) imaging, a technique capable of high-precision measurement of multiband Δi(k). At T = 90 mK, we visualize a set of Bogoliubov scattering interference wavevectors qj:j=1−5 consistent with eight gap nodes/minima that are all closely aligned to the (±1,±1) crystal lattice directions on both the α and β bands. Taking these observations in combination with other very recent advances in directional thermal conductivity [E. Hassinger et al., Phys. Rev. X 7, 011032 (2017)], temperature-dependent Knight shift [A. Pustogow et al., Nature 574, 72–75 (2019)], time-reversal symmetry conservation [S. Kashiwaya et al., Phys. Rev B, 100, 094530 (2019)], and theory [A. T. Rømer et al., Phys. Rev. Lett. 123, 247001 (2019); H. S. Roising, T. Scaffidi, F. Flicker, G. F. Lange, S. H. Simon, Phys. Rev. Res. 1, 033108 (2019); and O. Gingras, R. Nourafkan, A. S. Tremblay, M. Côté, Phys. Rev. Lett. 123, 217005 (2019)], the BQPI signature of Sr2RuO4 appears most consistent with Δi(k) having dx2−y2(B1g) symmetry.

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