Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Emergent Kondo scaling in iron-based superconductors AFe2As2 (A = K, Rb,
  Cs)   Unconventional superconductivity from heavy fermion (HF) is always observed
in f-electron systems, in which Kondo physics between localized f-electrons and
itinerant electrons plays an essential role. Whether HF superconductivity could
be achieved in other systems without f electrons, especially for d-electron
systems, is still elusive. Here, we experimentally study the origin of
d-electron HF behavior in iron-based superconductors (FeSCs) AFe2As2 (A = K,
Rb, Cs). Nuclear magnetic resonance on 75As reveals a universal
coherent-incoherent crossover with a characteristic temperature T*. Below T*, a
so-called 'Knight shift anomaly' is first observed in FeSCs, which exhibits a
scaling behavior similar to f-electron HF materials. Furthermore, the scaling
rule also regulates the manifestation of magnetic fluctuation. These results
undoubtedly support an emergent Kondo scenario for the d-electron HF behavior,
which suggests the AFe2As2 (A = K, Rb, Cs) as the first material realization of
d-electron HF superconductors.

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The categories of this paper are: plasm-ph
6
The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an
8
The categories of this paper are: hep-ex
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
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The categories of this paper are: acc-phys
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The categories of this paper are: cmp-lg
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The categories of this paper are: mtrl-th
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The categories of this paper are: econ
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The categories of this paper are: alg-geom
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The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
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The categories of this paper are: stat
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The categories of this paper are: solv-int
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The categories of this paper are: q-alg