Surface polaritons in a finite superlattice with a displaced layer in a quantizing magnetic field

A theoretical study is made of surface polaritons (SPs) in a weakly disorde red superlattice consisting of a finite number of infinitely extended two-d imensional electron layers (2DELs) placed in an external static quantizing magnetic field directed perpendicular to the 2DELs. The filling factor of t he Landau levels is assumed to be the same in all the 2DELs. The disorder i n the superlattice consists in having one of the interior 2DELs displaced f rom the position of periodicity by a certain distance Delta. The dispersion and energy characteristics of SPs are investigated in the case when a fini te superlattice is embedded in a uniform dielectric medium. It is shown tha t under conditions of the integer quantum Hall effect, all the characterist ics of the SPs are represented by quantized values. It is found that in a f inite, weakly disordered superlattice there exists a local SP mode whose pr operties differ substantially from those of the usual SP modes in a finite ordered superlattice. The conditions under which the phase and group veloci ties of the SPs in a finite, weakly disordered superlattice can be substant ially lower than in an isolated 2DEL are determined. It is found that when dissipation is taken into account, a new SP mode arises in a weakly disorde red superlattice-an additional SP whose properties depend strongly on the e lectron momentum relaxation frequency nu and on the displacement Delta. (C) 2000 American Institute of Physics. [S1063-777X(00)00702-7].