scholarly journals Spin-dependent conductivity of iron-based superconductors in a magnetic field

2015 ◽  
Vol 464 ◽  
pp. 68-73 ◽  
Author(s):  
M.O. Dzyuba ◽  
Yu.N. Chiang ◽  
D.A. Chareev ◽  
A.N. Vasiliev
2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Tsadik Kidanemariam ◽  
Gebregziabher Kahsay

This research work focuses on the theoretical investigation of the upper critical magnetic field,HC2; Ginzburg-Landau coherence length,ξGL(T); and Ginzburg-Landau penetration depth,λGL(T), for the two-band iron based superconductorsBaFe2(As1-xPx)2,NdO1-xFxFeAs, and LiFeAs. By employing the phenomenological Ginzburg-Landau (GL) equation for the two-band superconductorsBaFe2(As1-xPx)2,NdO1-xFxFeAs, and LiFeAs, we obtained expressions for the upper critical magnetic field,HC2; GL coherence length,ξGL; and GL penetration depth,λGL, as a function of temperature and the angular dependency of upper critical magnetic field. By using the experimental values in the obtained expressions, phase diagrams of the upper critical magnetic field parallel,HC2∥c, and perpendicular,HC2⊥c, to the symmetry axis (c-direction) versus temperature are plotted. We also plotted the phase diagrams of the upper critical magnetic field,HC2versus the angleθ. Similarly, the phase diagrams of the GL coherence length,ξGL, and GL penetration depth,λGL, parallel and perpendicular to the symmetry axis versus temperature are drawn for the superconductors mentioned above. Our findings are in agreement with experimental observations.


2017 ◽  
Vol 254 ◽  
pp. 6-9 ◽  
Author(s):  
S.K. Goi ◽  
B. Pradhan ◽  
Srikanta Behera ◽  
P.K. Parida ◽  
R.N. Mishra

SPIN ◽  
2018 ◽  
Vol 08 (02) ◽  
pp. 1850001 ◽  
Author(s):  
B. Pradhan ◽  
S. K. Goi ◽  
R. N. Mishra

We have proposed a mean field theoretical model in the coexistence of superconductivity and Jahn–Teller (JT) effect for the study of specific heat in iron-based superconductors in the presence of an external magnetic field. The superconducting (SC) gap and lattice strain energy expressions are calculated using Zubarev’s technique of double-time electron Green’s function and solved numerically. The specific heat jump at the critical temperatures are observed. Keeping fixed the SC transition temperature at 28[Formula: see text]K for the iron pnictide [Formula: see text] like superconductors, the coefficient of electronic specific heat [Formula: see text] at low temperatures is determined to be 5.75[Formula: see text]mJ/mol[Formula: see text]K2 in the pure SC state and 4.76[Formula: see text]mJ/mol[Formula: see text]K2 in the coexistence state of SC and JT effect which are in agreement with some experimental results. The effect of the external magnetic field on the specific heat is studied.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tsuyoshi Kawashima ◽  
Shigeki Miyasaka ◽  
Hirokazu Tsuji ◽  
Takahiro Yamamoto ◽  
Masahiro Uekubo ◽  
...  

AbstractThe structural flexibility at three substitution sites in LaFeAsO enabled investigation of the relation between superconductivity and structural parameters over a wide range of crystal compositions. Substitutions of Nd for La, Sb or P for As, and F or H for O were performed. All these substitutions modify the local structural parameters, while the F/H-substitution also changes band filling. It was found that the superconducting transition temperature $$T_{\text{c}}$$ T c is strongly affected by the pnictogen height $$h_{Pn}$$ h Pn from the Fe-plane that controls the electron correlation strength and the size of the $$d_{xy}$$ d xy hole Fermi surface (FS). With increasing $$h_{Pn}$$ h Pn , weak coupling BCS superconductivity switches to the strong coupling non-BCS one where electron correlations and the $$d_{xy}$$ d xy hole FS may be important.


2020 ◽  
Vol 2 (3) ◽  
Author(s):  
S.-F. Wu ◽  
W.-L. Zhang ◽  
V. K. Thorsmølle ◽  
G. F. Chen ◽  
G. T. Tan ◽  
...  

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