Coherent and ballistic switching effects in GaAs/AlGaAs nanojunctions

Abstract

Y-branched nanojunctions with lengths of the branching section down to 70 nm were fabricated from GaAs/AlGaAs modulation doped heterostructures by high resolution electron beam lithography and wet etching. At 4.2 K efficient switching of electrons into either of the branches is observed when a lateral electric field is applied. A positive bias voltage applied between the source and the two drains of the Y-branched nanojunctions leads to enhanced switching. Changing the gate voltage of one branch while keeping the other gate at a constant voltage value in the nonlinear transport regime leads to pronounced sawtooth oscillations of the conductance between source and the latter branch.