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Free keywords:
Charge-density wave; Electron transport; Entropy; In adsorption; Nanowire; Peierls transition; Si(111) surface
Abstract:
In this paper the recent experimental and theoretical progress in understanding the properties of the In-Si(111)(4 x 1)/(8 x 2) nanowire array a prototypical model system for exploring electron transport at the atomic scale is reviewed. Density functional theory (DFT) calculations illustrate how strongly structural, vibrational, and electronic properties of atomic-scale wires are intertwined. Numerical simulations of the nanowire optical response in comparison with recent measurements settle eventually the long-standing debate on the nanowire ground-state geometry in favor of hexagons. Soft phonon modes are found to transform the nanowire structurally between the insulating hexagon structure and metallic In zigzag chains. The subtle balance between the lower energy of the insulating phase and the larger vibrational entropy of the metallic wires is demonstrated to cause the temperature-dependent phase transition. The dynamic fluctuation model proposed earlier to explain the phase transition is shown to contradict the experimental information on the metal insulator transition of the nanowires. The influence of adatoms on the quantum transport and phase transition is discussed.
