OBSERVATION OF QUANTIZED CONDUCTANCE IN SPLIT-GATE IN0.53GA0.47AS IN0.77GA0.23AS/INP POINT CONTACTS USING CR/AU P-INP SCHOTTKY BARRIERS/

We report on the observation of quantized conductance in split-gate In 0.53Ga0.43As/Ga0.77In0.23As/InP point contacts. For the Schottky gates Au/Cr in combination with p-InP was used. As a result our split-gate point contacts show low pinch-off voltages and no measurable leakage c urrent through the gates. Up to five conductance steps were observed a t a temperature of 1.4 K. Our approach to fabricate split-gate Schottk y contacts can be used for quantum point contacts operating at higher temperatures as well as for superconductive quantum point contacts. (C ) 1998 American Institute of Physics.