Quantized conductance in bismuth nanowires at 4K

Conductance experiments on Bi nanowires at 4K, obtained with a Scanning Tunneling Microscope, are presented. The conductance of these Bi nanocontacts, formed between two Bi electrodes, exhibits plateaus at quantized values of G(0)=2e(2)/k, remaining basically constant during electrode separations of about 50 nm. This is the first time that such plateaus have been observed in semimetals. The histogram of conductance values, constructed with thousands of consecutive contact breakage conductance experiments, exhibits clear peaks at 1 and 2 G(0). In addition, current-voltage characteristics obtained during the contact breakage are presented, showing preliminar evidence of conductance quanta transitions due to the change in the applied bias voltage.