High-quality quantum point contacts in GaN/AlGaN heterostructures

We have fabricated quantum point contacts on a high-mobility GaN/AlGaN heterostructure using the split-gate technique. The conductance of our devices shows well-quantized plateaus, which spin-split in high perpendicular magnetic field. The g factor is derived from the point contact subband splitting versus perpendicular magnetic field. In addition to the well-resolved plateaus, we also observe evidence of ``0.7 structure'' which has been mainly investigated in the GaAs system. The work at Stanford was sponsored by the Office of Naval Research Young Investigator Program under award no. N00014-01-1-0569, and by a Seed Grant from Stanford University's Center for Integrated Systems.