Superconducting Gap in s±-Wave Iron-Based Superconductors

SPIN ◽  
2018 ◽  
Vol 08 (02) ◽  
pp. 1850006
Author(s):  
B. Pradhan ◽  
S. K. Goi ◽  
R. N. Mishra
Keyword(s):  
Nearest Neighbor ◽  
Energy Gap ◽  
S Wave ◽  
Iron Based Superconductors ◽  
Model Study ◽  
Superconducting Energy Gap ◽  
Wave Symmetry ◽  
Iron Based ◽  
Double Time ◽  
Gap Parameter

We present a theoretical model study of superconductivity for iron-based high-[Formula: see text] superconductors in s[Formula: see text]-wave symmetry, considering two degenerate orbitals and the electron hopping up to the third nearest neighbor as a two-orbital model. The analytic expression for the temperature dependence of the superconducting order parameter is derived by Zubarev’s technique of double time single particle Green’s function method and solved self-consistently. The effect of inter orbital hopping on the superconducting energy gap parameter and electronic specific heat is studied.

scholarly journals p-wave superconductivity in iron-based superconductors

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
E. F. Talantsev ◽  
K. Iida ◽  
T. Ohmura ◽  
T. Matsumoto ◽  
W. P. Crump ◽  
...  
Keyword(s):  
Energy Gap ◽  
Atomic Layer ◽  
P Wave ◽  
Physical Parameters ◽  
Superconducting Transition ◽  
Iron Based Superconductors ◽  
Wave Pairing ◽  
Superconducting Energy Gap ◽  
Wave States ◽  
Iron Based

Abstract The possibility of p-wave pairing in superconductors has been proposed more than five decades ago, but has not yet been convincingly demonstrated. One difficulty is that some p-wave states are thermodynamically indistinguishable from s-wave, while others are very similar to d-wave states. Here we studied the self-field critical current of NdFeAs(O,F) thin films in order to extract absolute values of the London penetration depth, the superconducting energy gap, and the relative jump in specific heat at the superconducting transition temperature, and find that all the deduced physical parameters strongly indicate that NdFeAs(O,F) is a bulk p-wave superconductor. Further investigation revealed that single atomic layer FeSe also shows p-wave pairing. In an attempt to generalize these findings, we re-examined the whole inventory of superfluid density measurements in iron-based superconductors and show quite generally that single-band weak-coupling p-wave superconductivity is exhibited in iron-based superconductors.

Phenomenological theory for ±s-wave superconducting states of iron-based superconductors

2010 ◽  
Vol 470 ◽  
pp. S372-S374 ◽  
Author(s):  
M. Machida ◽  
Y. Nagai ◽  
Y. Ota ◽  
N. Nakai ◽  
H. Nakamura ◽  
...  
Keyword(s):  
Phenomenological Theory ◽  
S Wave ◽  
Iron Based Superconductors ◽  
Iron Based

A PROPOSED NEW MEASUREMENT OF THE SUPERCONDUCTING GAP IN YBa2Cu3O7

2007 ◽  
Vol 21 (18n19) ◽  
pp. 3290-3293 ◽  
Author(s):  
G. L. ZHAO ◽  
D. BAGAYOKO
Keyword(s):  
Fermi Surface ◽  
Density Functional ◽  
Energy Gap ◽  
Interaction Matrix ◽  
Superconducting Gap ◽  
S Wave ◽  
Minor Variation ◽  
High Tc ◽  
Symmetry Properties ◽  
Superconducting Energy Gap

The superconducting energy gap of YBa 2 Cu 3 O 7 (YBCO) varies strongly with [Formula: see text] and from a sheet of the Fermi surface to another. The strong anisotropic superconducting gap in high Tc materials such as YBCO has led to conflicting d-wave and s-wave interpretations. We have utilized electronic wave functions from the ab-initio density functional calculation and the related electron-phonon interaction matrix elements for the calculation of the superconducting gap values of YBCO. We have found that the superconducting gap on one sheet of the Fermi surface around S-point only shows a minor variation from about 18 meV to 25 meV. Especially, there is no node on this sheet of the Fermi surface around the S-point. We propose a new test measurement of the superconducting gap of YBCO on this sheet of the Fermi surface around the S-point in the Brillouin zone. This measurement is expected to shed light on the gap symmetry properties of high Tc superconductors.

scholarly journals Pressure-dependent topological superconductivity on the surface of FeTe0.5Se0.5

2022 ◽  
Author(s):  
Chih-Kai Yang ◽  
Chi-Hsuan Lee
Keyword(s):  
Exchange Interaction ◽  
Density Functional ◽  
Applied Pressure ◽  
Bcs Theory ◽  
Superconducting Gap ◽  
Cooper Pairs ◽  
S Wave ◽  
Iron Based Superconductors ◽  
Iron Based ◽  
Critical Temperature Tc

Abstract FeTe1-xSex is a family of iron-based superconductors with its critical temperature (Tc) dependent on the composition of Se. A well-known Tc is 14.5 K for x = 0.45, which exhibits an s-wave superconducting gap between the topological superconducting surfaces states. Exchange interaction between the electrons has been proposed as the mechanism behind the formation of Cooper pairs for the sample of FeTe0.5Se0.5. In this article we provide further proof that exchange interaction, and hence the associated Tc, depends on the applied pressure on FeTe0.5Se0.5. Using density functional calculations for electrons and phonons and the Bardeen-Cooper-Schrieffer (BCS) theory for superconductivity, we found that Tc and superconducting gap for FeTe0.5Se0.5 soars under increasing compression, consistent with the results of experiment.

scholarly journals Theory of superconductivity in strongly correlated electron systems

2018 ◽  
Vol 32 (23) ◽  
pp. 1850257 ◽  
Author(s):  
Chyh-Hong Chern
Keyword(s):  
Energy Gap ◽  
Electron System ◽  
Real Space ◽  
Pairing Symmetry ◽  
Attractive Potential ◽  
S Wave ◽  
Strongly Correlated Electron ◽  
Correlated Electron Systems ◽  
Correlated Electron ◽  
Wave Symmetry

In the correlated electron system with the pseudogap, full-gapped domains and Fermi-arced domains coexist. These domains are created by the quantum-fluctuated antiferromagnetic correlation that generates the short-ranged attractive potential to produce the Fermi arcs and the superconductivity. In the full-gapped domains, s-wave or [Formula: see text]-wave symmetry of the electron pairs is favored. In the Fermi-arced domains, only [Formula: see text]-wave symmetry of pairs is stable. Superconductivity of different pairing symmetry coexists in different domains as well. Different from the Cooper pairs, the correlated electrons pair up in the real space with an energy gap. Gapless states, on the contrary, hinder the development of superconductivity.

scholarly journals Holographic p-wave superconductivity from higher derivative theory

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
Yan Liu ◽  
Guoyang Fu ◽  
Hai-Li Li ◽  
Jian-Pin Wu ◽  
Xin Zhang
Keyword(s):  
Normal State ◽  
Ac Conductivity ◽  
Energy Gap ◽  
Low Frequency ◽  
High Derivative ◽  
Superconducting Phase ◽  
P Wave ◽  
S Wave ◽  
Higher Derivative ◽  
Superconducting Energy Gap

AbstractWe construct a holographic SU(2) p-wave superconductor model with Weyl corrections. The high derivative (HD) terms do not seem to spoil the generation of the p-wave superconducting phase. We mainly study the properties of AC conductivity, which is absent in holographic SU(2) p-wave superconductor with Weyl corrections. The conductivities in superconducting phase exhibit obvious anisotropic behaviors. Along y direction, the conductivity $$\sigma _{yy}$$ σ yy is similar to that of holographic s-wave superconductor. The superconducting energy gap exhibits a wide extension. For the conductivity $$\sigma _{xx}$$ σ xx along x direction, the behaviors of the real part in the normal state are closely similar to that of $$\sigma _{yy}$$ σ yy . However, the anisotropy of the conductivity obviously shows up in the superconducting phase. A Drude-like peak at low frequency emerges in $$Re\sigma _{xx}$$ R e σ xx once the system enters into the superconducting phase, regardless of the behaviors in normal state.

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