Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Pairing symmetry of heavy fermion superconductivity in the
  two-dimensional Kondo-Heisenberg lattice model   In the two-dimensional Kondo-Heisenberg lattice model away from half-filled,
the local antiferromagnetic exchange coupling can provide the pairing mechanism
of quasiparticles via the Kondo screening effect, leading to the heavy fermion
superconductivity. We find that the pairing symmetry \textit{strongly} depends
on the Fermi surface (FS) structure in the normal metallic state. When
$J_{H}/J_{K}$ is very small, the FS is a small hole-like circle around the
corner of the Brillouin zone, and the s-wave pairing symmetry has a lower
ground state energy. For the intermediate coupling values of $J_{H}/J_{K}$, the
extended s-wave pairing symmetry gives the favored ground state. However, when
$J_{H}/J_{K}$ is larger than a critical value, the FS transforms into four
small hole pockets crossing the boundary of the magnetic Brillouin zone, and
the d-wave pairing symmetry becomes more favorable. In that regime, the
resulting superconducting state is characterized by either nodal d-wave or
nodeless d-wave state, depending on the conduction electron filling factor as
well. A continuous phase transition exists between these two states. This
result may be related to the phase transition of the nodal d-wave state to a
fully gapped state, which is recently observed in Yb doped CeCoIn$_{5}$.

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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: supr-con
13
The categories of this paper are: quant-ph
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The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
29
The categories of this paper are: funct-an
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: math-ph
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The categories of this paper are: q-alg
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The categories of this paper are: physics
0
The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc