Conductance quantization in metallic nanostructures

Resumo

In this project, we will study the quantized conductance of nanowires or point contacts in the ballistic regime. In particular, we have already observed that quantum point contacts (QPC) generated by mechanically vibrating macroscopic wires, display many cases of non-integer quantized conductance values. Here, we will concentrate in the origine of these fractional quantum conductance effects. To address this problem, we suggest to perform precise measurement of the fractional values, and operate the QPC in UHV chamber. The clean environment of this instrument will allow the study of contamination/impurity effects. In addition, we intend to build a mechanically controllable break junctions where metallic nanostructures will be obtained with the use of the precise and fine piezo element based manipulation system, where the nanowire may be elongated in a controlled way, both from the point of view of time scale and mechanical stability. (AU)