Observation of a ubiquitous three-dimensional superconducting gap function in optimally-doped Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2
Nature Physics 7, 198-202 (2011) The iron-pnictide superconductors have a layered structureformed by stacks of FeAs planes from which the superconductivity originates. Given the multiband and quasi three-dimensional \cite{3D_SC} (3D) electronic structure of these high-temperature superconductors, kn...
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Main Authors | , , , , , , , , , , , , |
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Format | Journal Article |
Language | English |
Published |
20.06.2010
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Subjects | |
Online Access | Get full text |
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Summary: | Nature Physics 7, 198-202 (2011) The iron-pnictide superconductors have a layered structureformed by stacks of
FeAs planes from which the superconductivity originates. Given the multiband
and quasi three-dimensional \cite{3D_SC} (3D) electronic structure of these
high-temperature superconductors, knowledge of the quasi-3D superconducting
(SC) gap is essential for understanding the superconducting mechanism. By using
the \KZ-capability of angle-resolved photoemission, we completely determined
the SC gap on all five Fermi surfaces (FSs) in three dimensions on \BKFAOP
samples. We found a marked \KZ dispersion of the SC gap, which can derive only
from interlayer pairing. Remarkably, the SC energy gaps can be described by a
single 3D gap function with two energy scales characterizing the strengths of
intralayer $\Delta_1$ and interlayer $\Delta_2$ pairing. The anisotropy ratio
$\Delta_2/\Delta_1$, determined from the gap function, is close to the c-axis
anisotropy ratio of the magnetic exchange coupling $J_c/J_{ab}$ in the parent
compound \cite{NeutronParent}. The ubiquitous gap function for all the 3D FSs
reveals that pairing is short-ranged and strongly constrain the possible
pairing force in the pnictides. A suitable candidate could arise from
short-range antiferromagnetic fluctuations. |
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DOI: | 10.48550/arxiv.1006.3958 |