Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Highly anisotropic quasiparticle interference patterns in the
  spin-density wave state of the iron pnictides   We investigate the impurity scattering induced quasiparticle interference in
the ($\pi, 0$) spin-density wave phase of the iron pnictides. We use a five
orbital tight binding model and our mean field theory in the clean limit
captures key features of the Fermi surface observed in angle-resolved
photoemission. We use a t-matrix formalism to incorporate the effect of doping
induced impurities on this state. The impurities lead to a spatial modulation
of the local density of states about the impurity site, with a periodicity of
$\sim 8a_{{\rm Fe}-{\rm Fe}}$ along the antiferromagnetic direction. The
associated momentum space quasiparticle interference pattern is anisotropic,
with major peaks located at $\sim (\pm \pi/4,0)$, consistent with spectroscopic
imaging scanning tunneling microscopy. We trace the origin of this pattern to
an elliptical contour of constant energy around momentum (0,0), with major axis
oriented along the (0,1) direction, in the mean field electronic structure.

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The categories of this paper are: dg-ga
3
The categories of this paper are: physics
16
The categories of this paper are: stat
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph