Low energy impurity kink in the normal and anomalous self-energies in Bi-cuprate superconductors

2015 ◽  
Vol 29 (25n26) ◽  
pp. 1542005
Author(s):  
Jin Mo Bok ◽  
Jong Ju Bae ◽  
Seung Hwan Hong ◽  
X. J. Zhou ◽  
Han-Yong Choi
Keyword(s):  
Cuprate Superconductors ◽  
Energy Analysis ◽  
Energy Gap ◽  
Low Energy ◽  
The Self ◽  
Energy Term ◽  
Impurity Effects ◽  
Self Energy ◽  
Superconducting Energy Gap ◽  
Arpes Data

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.

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

2004 ◽  
Vol 69 (10) ◽  
Author(s):  
I. K. Yanson ◽  
S. I. Beloborod’ko ◽  
Yu. G. Naidyuk ◽  
O. V. Dolgov ◽  
A. A. Golubov
Keyword(s):  
Energy Gap ◽  
Self Energy ◽  
Superconducting Energy Gap

Unrelated BCS-like pairing pseudogap and critical superconducting transition temperature in various cuprate compounds

2018 ◽  
Vol 32 (18) ◽  
pp. 1850195
Author(s):  
S. Dzhumanov ◽  
E. X. Karimboev ◽  
Sh. S. Djumanov
Keyword(s):  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Order Parameter ◽  
Cuprate Superconductors ◽  
Energy Gap ◽  
Characteristic Temperature ◽  
Superconducting Order Parameter ◽  
Superconducting Transition ◽  
Gap Formation ◽  
Arpes Data

The smooth evolution of the energy gap observed in the tunneling and angle-resolved photoemission spectra (ARPES) of high-[Formula: see text] cuprates with lowering the temperature from a pseudogap state above the critical temperature [Formula: see text] to a superconducting state below [Formula: see text], has been poorly interpreted as the evidence that the pseudogap must have the same origin as the superconducting order parameter, and therefore, must be related to [Formula: see text]. We argue that such an explanation of the tunneling gap and ARPES data is misleading. We show that the BCS-like energy gap (or pseudogap) opening in the electronic excitation spectrum of underdoped-to-overdoped cuprates at a characteristic temperature [Formula: see text] and the true superconducting order parameter appearing only at [Formula: see text] are unrelated. The superconducting phenomenon in unconventional cuprate superconductors is fundamentally different from the BCS-like pairing of fermionic quasiparticles, and the superconducting transition temperature [Formula: see text] is not determined by the BCS-like gap formation. The unusual superconducting order parameter in these high-[Formula: see text] materials appears at [Formula: see text] and coexists with the BCS-like gap (or pseudogap) below [Formula: see text].

STRONG SU(2) BREAKING AND MASS SPLITTINGS IN PSEUDOSCALAR MESONS

1996 ◽  
Vol 11 (29) ◽  
pp. 5245-5259 ◽  
Author(s):  
A. N. MITRA
Keyword(s):  
Mass Difference ◽  
Dynamical Symmetry ◽  
Quark Condensate ◽  
Low Energy ◽  
The Self ◽  
Quark Loop ◽  
Self Energy ◽  
A Value ◽  
Pseudoscalar Mesons ◽  
Vector Exchange

The mass splittings within the SU(2) multiplets of pseudoscalar mesons (π, K, D, B) are used as a laboratory to determine the mass difference between d and u quarks (current), through the simplest (two-point) quark-loop diagrams for the self-energies of the corresponding hadrons, together with the associated quark-condensate diagrams within the loops. The second-order e.m. correction is also calculated with a photon line joining the two opposite quark lines in the self-energy loop. The basic ingredient is a hadron–quark-vertex function generated from a vector-exchange-like (chirally invariant) four-fermion Lagrangian (with current quarks) under dynamical symmetry breaking (DχSB), precalibrated to spectroscopy and other important low-energy amplitudes. The results which are expressed as proportional to the u−d mass difference δc, but are otherwise free from any adjustable parameters, reproduce in a rather accurate way all the SU(2) mass differences (from kaon to bottom) with δc = 4.0 MeV, when all the three self-energy diagrams are included. The pion receives only e.m. contributions with a value 5.24 MeV.

scholarly journals ON THE NONRELATIVISTIC LIMIT OF THE φ4 THEORY IN 2+1 DIMENSIONS

1996 ◽  
Vol 11 (36) ◽  
pp. 2825-2836 ◽  
Author(s):  
M. GOMES ◽  
J.M.C. MALBOUISSON ◽  
A.J. DA SILVA
Keyword(s):  
Quantum Theory ◽  
Scalar Field ◽  
Scattering Amplitude ◽  
Nonrelativistic Limit ◽  
Low Energy ◽  
The Self ◽  
Energy Correction ◽  
Real Scalar ◽  
Self Energy

We study the nonrelativistic limit of the quantum theory of a real scalar field with quartic self-interaction. The two-body scattering amplitude is written in such way as to separate the contributions of high and low energy intermediary states. From this result and the two-loop computation of the self-energy correction, we determine an effective nonrelativistic action.

scholarly journals Incoherent superconductivity well above Tc in high-Tc cuprates - harmonizing the spectroscopic and thermodynamic data

2020 ◽  
Author(s):  
James Storey
Keyword(s):  
Field Dependence ◽  
Cuprate Superconductors ◽  
Energy Gap ◽  
Spectroscopic Properties ◽  
Superconducting Gap ◽  
Superconducting Transition ◽  
Complex Materials ◽  
Self Energy ◽  
Dependent Pair ◽  
Breaking Term

© 2017 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft. Cuprate superconductors have long been known to exhibit an energy gap that persists high above the superconducting transition temperature (Tc). Debate has continued now for decades as to whether it is a precursor superconducting gap or a pseudogap arising from some competing correlation. Failure to resolve this has arguably delayed explaining the origins of superconductivity in these highly complex materials. Here we effectively settle the question by calculating a variety of thermodynamic and spectroscopic properties, exploring the effect of a temperature-dependent pair-breaking term in the self-energy in the presence of pairing interactions that persist well above Tc.We start by fitting the detailed temperature-dependence of the electronic specific heat and immediately can explain its hitherto puzzling field dependence. Taking this same combination of pairing temperature and pairbreaking scattering we are then able to simultaneously describe in detail the unusual temperature and field dependence of the superfluid density, tunneling, Raman and optical spectra, which otherwise defy explanation in terms a superconducting gap that closes conventionally at Tc. These findings demonstrate that the gap above Tc in the overdoped regime likely originates from incoherent superconducting correlations, and is distinct from the competing-order pseudogap that appears at lower doping.

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

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.

scholarly journals Incoherent superconductivity well above Tc in high-Tc cuprates - harmonizing the spectroscopic and thermodynamic data

2020 ◽  
Author(s):  
James Storey
Keyword(s):  
Field Dependence ◽  
Cuprate Superconductors ◽  
Energy Gap ◽  
Spectroscopic Properties ◽  
Superconducting Gap ◽  
Superconducting Transition ◽  
Complex Materials ◽  
Self Energy ◽  
Dependent Pair ◽  
Breaking Term

© 2017 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft. Cuprate superconductors have long been known to exhibit an energy gap that persists high above the superconducting transition temperature (Tc). Debate has continued now for decades as to whether it is a precursor superconducting gap or a pseudogap arising from some competing correlation. Failure to resolve this has arguably delayed explaining the origins of superconductivity in these highly complex materials. Here we effectively settle the question by calculating a variety of thermodynamic and spectroscopic properties, exploring the effect of a temperature-dependent pair-breaking term in the self-energy in the presence of pairing interactions that persist well above Tc.We start by fitting the detailed temperature-dependence of the electronic specific heat and immediately can explain its hitherto puzzling field dependence. Taking this same combination of pairing temperature and pairbreaking scattering we are then able to simultaneously describe in detail the unusual temperature and field dependence of the superfluid density, tunneling, Raman and optical spectra, which otherwise defy explanation in terms a superconducting gap that closes conventionally at Tc. These findings demonstrate that the gap above Tc in the overdoped regime likely originates from incoherent superconducting correlations, and is distinct from the competing-order pseudogap that appears at lower doping.

scholarly journals How to pin down the pairing interaction for high Tc superconductivity in cuprates

2018 ◽  
Vol 32 (17) ◽  
pp. 1840026 ◽  
Author(s):  
Han-Yong Choi ◽  
Jin Mo Bok
Keyword(s):  
Frequency Dependence ◽  
Momentum Distribution ◽  
Emission Spectroscopy ◽  
Cuprate Superconductors ◽  
Theoretical Calculations ◽  
The Self ◽  
Pairing Interaction ◽  
High Tc ◽  
High Tc Superconductivity ◽  
Arpes Data

The normal and pairing self-energies are the microscopic quantities which reflect and characterize the underlying interaction in superconductors. The momentum and frequency dependence of the self-energies, therefore, provides the experimental criteria which can single out the long sought-after pairing interaction among many proposed ideas. This line of research to pin down the pairing interaction for the cuprate superconductors has been carried out with some success by analyzing the momentum distribution curves (MDCs) of laser angle-resolved photo-emission spectroscopy (ARPES) data. Some progress and results are presented and compared with theoretical calculations based on leading proposals. Comments are made on the proposed scenarios from the comparisons.

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