The anomalous electronic structure of electron-doped cuprate superconductors by considering the next higher harmonics of the superconducting gap

2021 ◽  
pp. 2150256
Author(s):  
Jihong Qin
Keyword(s):  
Electron Spectrum ◽  
Cuprate Superconductors ◽  
Mean Field Theory ◽  
Mean Field ◽  
Anomalous Behavior ◽  
Momentum Dependence ◽  
Higher Harmonics ◽  
Critical Strength ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Energy And Momentum

Based on the self-consistent mean field theory by considering the next higher harmonics of the superconducting (SC) gap, we discuss the energy and momentum dependence of the electron spectrum in electron-doped cuprate superconductors. By calculation of the electron spectral function, it is shown that the weight of the electron spectrum at the Fermi energy is strongly redistributed by the next higher harmonics of the SC gap in electron-doped cuprate superconductors, especially for the antinodal region. At the antinodal region, the weight of the electron spectrum at the Fermi surface increases with the increase of next higher harmonics term, reaches the maximum at a critical strength, then decreases when the next higher harmonics is larger. Our theoretical results show that the variation of the SC gap with the next higher harmonics can explain the anomalous behavior of the electron spectrum and different angle-resolved photoemission spectroscopy experimental results of different samples of electron-doped cuprate superconductors. Moreover, the magnitude of the SC gap can be suppressed by the next higher harmonics, which may be one of the reasons for the smaller SC gap in electron-doped cuprate superconductors. Obvious topological change happens in the SC gap at a critical strength of the next higher harmonics.

scholarly journals Computational Modeling of Tensile Stress Effects on the Structure and Stability of Prototypical Covalent and Layered Materials

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1483 ◽  
Author(s):  
Hocine Chorfi ◽  
Álvaro Lobato ◽  
Fahima Boudjada ◽  
Miguel A. Salvadó ◽  
Ruth Franco ◽  
...  
Keyword(s):  
Tensile Stress ◽  
Density Functional ◽  
Stability Limit ◽  
Density Functional Theory Calculations ◽  
Layered Materials ◽  
Stress Conditions ◽  
Ideal Strength ◽  
Critical Strength ◽  
Calculated Stress ◽  
The Stability

Understanding the stability limit of crystalline materials under variable tensile stress conditions is of capital interest for technological applications. In this study, we present results from first-principles density functional theory calculations that quantitatively account for the response of selected covalent and layered materials to general stress conditions. In particular, we have evaluated the ideal strength along the main crystallographic directions of 3C and 2H polytypes of SiC, hexagonal ABA stacking of graphite and 2H-MoS 2 . Transverse superimposed stress on the tensile stress was taken into account in order to evaluate how the critical strength is affected by these multi-load conditions. In general, increasing transverse stress from negative to positive values leads to the expected decreasing of the critical strength. Few exceptions found in the compressive stress region correlate with the trends in the density of bonds along the directions with the unexpected behavior. In addition, we propose a modified spinodal equation of state able to accurately describe the calculated stress–strain curves. This analytical function is of general use and can also be applied to experimental data anticipating critical strengths and strain values, and for providing information on the energy stored in tensile stress processes.

A molecular dynamics study on the thickness and post-critical strength of carbon nanotubes

2012 ◽  
Vol 94 (4) ◽  
pp. 1352-1358 ◽  
Author(s):  
Nuno Silvestre ◽  
Bruno Faria ◽  
José N. Canongia Lopes
Keyword(s):  
Carbon Nanotubes ◽  
Molecular Dynamics ◽  
Critical Strength

Fracture Energy and Critical Strength of High Molecular Weight Glassy Polymers

1990 ◽  
Vol 214 ◽  
Author(s):  
Antonios G. Mikos ◽  
Nikolaos A. Peppas
Keyword(s):  
Molecular Weight ◽  
Fracture Energy ◽  
Molecular Model ◽  
Mesh Size ◽  
Glassy Polymers ◽  
Segment Length ◽  
Critical Strength ◽  
Theoretical Predictions ◽  
Entanglement Network ◽  
Chain Entanglements

ABSTRACTThe fracture energy and the critical strength of glassy polymers with molecular weight larger than the critical value for the onset of chain entanglements are proportional to the number of chain segments entangled about a unit plane. A new molecular model is presented to calculate the crossing density of these chain segments when the segment length is a stochastic variable. The crossing density depends on the mesh size of the entanglement network and the number of entanglement network strands per unit volume. Theoretical predictions of the variation of the fracture energy and strength with the molecular weight are compared with experimental results for various glassy polymers.

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