Real-space transfer of electrons in a random potential relief: A possible mechanism of current instability in GaAs/AlGaAs heterostructures

A possible mechanism of lateral current instability observed in GaAs/AlGaAs heterostructures is proposed. We show both theoretically and experimentall y that the instability is originated from the electron transport in a heavi ly doped layer of AlGaAs, which is strongly compensated due to the presence of DX-centers. Real-space transfer of hot electrons from a percolation clu ster net to random potential wells results in the appearance of a hidden ne gative differential conductivity. The formation of an electric field domain causes the current through the 2D electron gas to collapse. Experimental r esults proving this mechanism are given.