Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Transport through quantum spin Hall insulator/metal junctions in
  graphene ribbons   Quantum spin Hall insulator/metal interfaces are formed in graphene ribbons
with intrinsic spin-orbit coupling by selectively doping two regions creating a
potential step. For a clean graphene ribbon, the transmission of the
topological edge states through a n-n or p-p junction is perfect irrespective
of the ribbon termination, width, and potential step parameters due to the
orthogonality of incoming and outgoing edge channels. This is shown numerically
for an arbitrary crystallographic orientation of the ribbon and proven
analytically for zigzag and metallic armchair boundary conditions. In
disordered ribbons, the orthogonality between left- and right-movers is in
general destroyed and backscattering sets in. However, transmission approaches
one by increasing the ribbon's width, even in the presence of strong edge
roughness.

37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
32
The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin