Description
We derive the effective field theory describing a classical
magnetic
impurity located near the edge of a two-dimensional quantum
spin Hall
insulator focusing on the regime where the impurity
potential is larger
than the band gap. We show that, due to the new features
brought about by
dimensionality, the low energy physics is universally
described by a
resonant level model coupled to the one-dimensional (1D)
channel of
interacting edge electrons. Away from resonance, the
effective 1D model
reduces to stuctureless impurity in a Tomonaga-Luttinger
liquid. On the
other hand, in the resonant regime, the transmission is
suppressed both
for weak to moderately attractive and repulsive interactions.
Ref: arXiv:1609.06227
