Max Planck Institute for Dynamics and Self-Organization -- Department for Nonlinear Dynamics and Network Dynamics Group
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How branching can change the conductance of ballistic semiconductor devices

Denis Maryenko, Jakob J. Metzger, Ragnar Fleischmann, Theo Geisel, Vladimir Umansky, Frank Ospald, Klaus v. Klitzing, and Jurgen Smet (2012)

Phys. Rev. B 85:195329.  ( BibTeX export )

We demonstrate that branching of the electron flow in semiconductor nanostructures can strongly affect macroscopic transport quantities and can significantly change their dependence on external parameters compared to the ideal ballistic case, even when the system size is much smaller than the mean free path. In a corner- shaped ballistic device based on a GaAs/AlGaAs two-dimensional electron gas, we observe a splitting of the commensurability peaks in the magnetoresistance curve. We show that a model which includes a random disorder potential of the two-dimensional electron gas can account for the random splitting of the peaks that result from the collimation of the electron beam. The shape of the splitting depends on the particular realization of the disorder potential. At the same time, magnetic focusing peaks are largely unaffected by the disorder potential.