Determination of intrinsic lifetime of edge magnetoplasmons
  It is known that peculiar plasmons whose frequencies are purely imaginary exist in the interior of a two-dimensional electronic system described by the Drude model. We show that when an external magnetic field is applied to the system, these bulk plasmons are still non-oscillating and are isolated from the magnetoplasmons by the energy gap of the cyclotron frequency. These are mainly in a transverse magnetic mode and can combine with a transverse electronic mode locally at an edge of the system to form edge magnetoplasmons. With this observation, we reveal the intrinsic long lifetime of edge magnetoplasmons for the first time. 
Ken-ichi Sasaki, Shuichi Murakami, Yasuhiro Tokura, Hideki Yamamoto
cond-mat.mes-hall cond-mat.mtrl-sci