Quantized conductance in an in-plane gated In0.53Ga0.47As quantum point contact

We report quantized conductance in a 500 nm wide In_0.53Ga_0.47As quantum point contact defined by 100 nm wide trenches. The surrounding two-dimensional electron gas was used as gate. Electron beam lithography and reactive ion etching with BCl₃ formed the trenches. Quantized conductance in steps of 2e²/h as well as one additional step at 0.7(2e²/h) was observed at 4.8 K. Conductance oscillations superimpose the plateaus at 0.3 K. A possible explanation for these resonance structures is a quantum interference of electron waves between the boundaries to the two-dimensional source and drain region.