Physics – Condensed Matter – Superconductivity
Scientific paper
2009-11-12
Phys. Rev. B 81, 060505(R) (2010)
Physics
Condensed Matter
Superconductivity
Scientific paper
10.1103/PhysRevB.81.060505
The London penetration depth, $\lambda$, is directly related to the density, $n_{s}$, of the Cooper pairs ($\lambda^{2}\propto 1/n_{s}$) and its variation with temperature provides valuable insight into the pairing mechanism. Here we study the evolution with doping of the temperature dependence of the in-plane ($\lambda_{ab}$) and out-of-plane ($\lambda_{c}$) penetration depths in single crystals of electron-doped Ba(Fe$_{1-x}$Ni$_x$)$_2$As$_2$. As is the case for other pnictides, $\lambda(T) \sim T^n$ over the whole doping range and this behavior extends down to at least $T=T_c/100$, setting a very small upper limit on the gap minimum. Furthermore, in the overdoped regime: 1) the exponent $n$ becomes substantially smaller than 2, which is incompatible with the models that explain power-law behavior to be due to scattering; 2) the exponent $n$ becomes anisotropic, with $\lambda_{c}(T)$ showing a clear $T$-linear behavior over a large temperature interval. These findings suggest that in the overdoped regime the superconducting gap in iron-based pnictide superconductors develops nodal structure, which unlike in the cuprates, cannot be understood within a two-dimensional picture.
Bud'ko Sergey L.
Canfield Paul. C.
Gordon R. T.
Kim Hungsoo
Kogan Vladimir G.
No associations
LandOfFree
Three-dimensional nodal superconducting gap in single crystals Ba(Fe$_{1-x}$Ni$_x$)$_2$As$_2$ does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Three-dimensional nodal superconducting gap in single crystals Ba(Fe$_{1-x}$Ni$_x$)$_2$As$_2$, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Three-dimensional nodal superconducting gap in single crystals Ba(Fe$_{1-x}$Ni$_x$)$_2$As$_2$ will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-148594