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Related papers: Anisotropic superconducting gaps in YNi$_2$B$_2$C:…

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We investigate the electronic properties of type-II superconducting Nb(110) in an external magnetic field. Scanning tunneling spectroscopy reveals a complex vortex shape which develops from circular via coffee bean-shaped to elliptical when…

We implement the Bogoliubov-de Gennes (BdG) equation in a screened Korringa-Kohn-Rostoker (KKR) method for solving, self-consistently, the superconducting state for 3d crystals. This method combines the full complexity of the underlying…

Superconductivity · Physics 2020-02-26 Tom G. Saunderson , James F. Annett , Balázs Újfalussy , Gábor Csire , Martin Gradhand

The microwave complex surface impedance Z_s of Y(Ni_{1-x}Pt_x)_2B_2C was measured at 0.5 K under magnetic fields H up to 7T. In nominally pure YNi_2B_2C, which is a strongly anisotropic s-wave superconductor, the flux flow resistivity…

Superconductivity · Physics 2009-11-07 K. Takaki , A. Koizumi , T. Hanaguri , M. Nohara , H. Takagi , K. Kitazawa , Y. Kato , Y. Tsuchiya , H. Kitano , A. Maeda

The anisotropic superconducting state properties in Cu0.03TaS2 have been investigated by magnetization, magnetoresistance, and specific heat measurements. It clearly shows that Cu0.03TaS2 undergoes a superconducting transition at TC = 4.03…

In the iron pnictide superconductors, two distinct unconventional mechanisms of superconductivity have been put forth: One is mediated by spin fluctuations leading to the s+- state with sign change of superconducting gap between the hole…

Phonon or electron mediated weak BCS attraction is enough to have high critical temperature if a van Hove anomaly is at work. This could apply to electron doped compounds and also to compounds with CuO$_2$ planes overdoped in holes, where…

Superconductivity · Physics 2007-05-23 J. Friedel , M. Kohmoto

We report low temperature scanning tunneling microscopy and spectroscopy studies of Ni-Bi films grown by molecular beam epitaxy. Highly anisotropic and twofold symmetric superconducting gaps are revealed in two distinct composites, Bi-rich…

Superconductivity · Physics 2018-05-01 Wen-Lin Wang , Yi-Min Zhang , Yan-Feng Lv , Hao Ding , Lili Wang , Wei Li , Ke He , Can-Li Song , Xu-Cun Ma , Qi-Kun Xue

The electronic bandstructure of Au$_2$Pb has a Dirac cone which gaps when undergoing a structural transition into a low temperature superconducting phase. This suggests that the superconducting phase ($T_c=1.1$ K) might hold topological…

It is shown within the weak-coupling model that the macroscopic superconducting anisotropy for materials with the gap varying on the Fermi surface cannot be characterized by a single number, unlike the case of clean materials with isotropic…

Superconductivity · Physics 2009-11-07 V. G. Kogan

The optical properties of YNi$_2$B$_2$C are studied by using the first-principles full-potential linearized augmented plane wave (FLAPW) method within the local density approximation. Anisotropic behavior is obtained in the optical…

Superconductivity · Physics 2009-11-07 S. J. Youn , B. I. Min , A. J. Freeman

The microscopic mechanism governing the zero-resistance flow of current in some iron-based, high-temperature superconducting materials is not well understood up to now. A central issue concerning the investigation of these materials is…

Recent thermal conductivity measurements on $UPt_3$ single crystals by Lussier et al. indicate the existence of a strong b--c anisotropy in the superconducting state. We calculate the thermal conductivity in various unconventional candidate…

Condensed Matter · Physics 2009-10-22 A. Fledderjohann , P. J. Hirschfeld

We present a new method of determining the anisotropy of the gap function in layered high-Tc superconductors. Careful inelastic neutron scattering measurements at low temperature of the phonon dispersion curves in the (100) direction in…

Condensed Matter · Physics 2009-10-22 Michael E. Flatte

The discovery of high-transition temperature (high-Tc) superconductivity near antiferromagnetism in iron arsenides raised the possibility of an unconventional superconducting mechansim1-8. The observation of clear Fermi surfaces and…

Dependences of low temperature behavior and anisotropy of various physical quantities for pure unconventional superconductors upon a particular form of momentum direction dependence for the superconducting order parameter (within the…

Condensed Matter · Physics 2009-10-28 Yu. S. Barash , A. A. Svidzinsky

We report the discovery of superconductivity in Nb$_3$Pd$_{x}$Se$_7$ with a $x$-dependent superconducting transition-temperature as high as $T_c \simeq 2.1 $ K for $x \simeq0.7$ (middle point of the resistive transition). Needle-like single…

Superconductivity · Physics 2013-07-16 Q. Zhang , D. Rhodes , B. Zeng , T. Besara , T. Siegrist , M. D. Johannes , L. Balicas

We studied nearly optimally Ni-substituted BaFe$_{2-x}$Ni$_x$As$_2$ (BFNA) single crystals with $T_C \approx 18.5$\,K. In irreversible magnetization measurements, we determined the field dependence of the critical-current density and…

Recent angle-resolved spectroscopy in BiS$_2$-based superconductors has indicated that the superconducting gap amplitude possesses remarkable anisotropy and/or a sign change on a small Fermi pocket around $X$ point. It implies a possibility…

Superconductivity · Physics 2017-07-26 Katsuhiro Suzuki , Hidetomo Usui , Kazuhiko Kuroki , Hiroaki Ikeda

We have performed ultrahigh-resolution angle-resolved photoemission spectroscopy to directly observe the large superconducting (SC) gap anisotropy (GA) of YNi2B2C. The result shows large SC GA with a smooth variation along an intersection…

Superconductivity · Physics 2008-12-03 T. Baba , T. Yokoya , S. Tsuda , T. Watanabe , M. Nohara , H. Takagi T. Oguchi , S. Shin

The point-contact (PC) spectra of the Andreev reflection dV/dI curves of the superconducting rare-earth nickel borocarbide ErNi2B2C (Tc=11 K) have been analyzed in the "one-gap" and "two-gap" approximations using the generalized…