Quasi-one-dimensional transport of nondegenerate electrons in two-dimensional systems with a fluctuation potential

A threshold vanishing of the Hall emf with decreasing gate voltage is observed at approximate to 77 K in semiconductor systems which are disordered as a result of a high built-in charge density near the plane of the 2D-electron channel. The effect is observed at a channel conductivity a approximate to e(2)/h and is due to a transition to nondegenerate-electron transport via a 2D percolation cluster having a quasi-1D character of the conduction. We have established that the conductance of "short" structures, having a length of the order of the correlation length of a percolation cluster, equals approximate to e(2)/h per electron and is determined by isolated percolation paths having a lowered percolation threshold. These phenomena are a general property of disordered 2D systems. (C) 1997 American Institute of Physics.