One-dimensional probability density observed using scanned gate microscopy

Using scanned gate microscopy, we observed transconductance structure relating to the transverse electron probability density of a quasi-one-dimensional electron system (Q1DES). The scanned gate created a movable scatterer to modify the transmission probability of the highest transmitted one-dimensional (1D) subband. Structure was seen for the first three 1D subbands, in addition to transconductance oscillations indicative of 1D ballistic transport. The Q1DES was electrostatically defined from a subsurface two-dimensional electron system created at a GaAs/AlGaAs heterojunction. The Q1DES confining potential was modelled as flat in the middle with parabolic walls, and Schrödinger's equation solved numerically using a finite-difference method. Using this model, the experimental Q1DES width and 1D subband energy spacings were deduced.