電気化学電位によるAuナノワイヤーの構造制御

Gold nano wire was mechanically fabricated in solution to study their quantized conductance behavior under the electrochemical potential control. A 1 nm length mono atomic wire showing a unit value of the quantized conductance (G0 = 2e^2/h) was fabricated in solution at room temperature by choosing appropriate electrochemical potential and electrolyte. As well as a unit value, several fractional values were also recognized at the quantization. Intensity of the fractional conductance peak at 0.6 G0 in the histogram increased as the electrochemical potential of the wire became negative. Conductance trace proves that the fractional peak in the histogram is due to reversible conductance fluctuation between a unit (1 G0) and the fractional value (0.6 G0). These experimental results strongly suggest the formation of a gold mono-atomic wire showing reversible phase transition between a dimerized state and an equal spacing state. Possibility regarding the mono-atomic wire as a predecessor for Pierls transition in 1D metal systems was discussed.