Experimental investigation of the damping of low-frequency edge magnetoplasmons in GaAs-${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As heterostructures

A detailed experimental study of damping and velocity of low-frequency edge magnetoplasmons in GaAs-${\mathrm{Al}}_{\mathit{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As heterostructures is presented. The damping is observed to be frequency dependent at filling factors close to integer values. The magnitude of the damping increases with frequency, the dependence being somewhere between linear and quadratic. This finding indicates that the damping of low-frequency edge magnetoplasmons cannot be described by the effective relaxation time. The experimental results are discussed in terms of existing models of low-frequency edge magnetoplasmons.