Manifestations of incompressible strips in the edge magnetoplasmon spectrum in the quantum Hall effect regime

The behavior of the main edge magnetoplasmon mode in the quantum Hall effect (QHE) regime has been analyzed by the method of optical detection of resonance microwave absorption. Near a filling factor of $2$ at a temperature of about $0.3$ K, the main edge mode splits into two modes seemingly due to broadening of the incompressible strip at the edge of the two-dimensional electron gas under such conditions.