HOPPING TRANSPORT ALONG A POTENTIAL WALL - OSCILLATIONS OF THE MAGNETORESISTANCE IN A PARALLEL FIELD

We study the variable-range-hopping magnetoresistance of a 2D system o f localized electrons in the presence of a boundary parallel to the pl ane of the 2D electrons. In a magnetic field B parallel to the plane, the magnetoresistance oscillates with B if the distance between the pl ane and the boundary is not too large. These oscillations result from the interference of the amplitude of the in-plane tunneling path with the amplitude of the path reflected by the boundary. We show that the orbital shrinkage effect, altering differently both amplitudes, strong ly enhances the interference. At the same time, the amplitude of oscil lations appears to be ma compared to the general increase in the resis tance caused by the orbital shrinkage. The most pronounced effect of t he interference can be seen in the differential magnetoresistance R-1( B)partial derivative R(B)/partial derivative B, which we analyze numer ically.