Transport in defective quasi-one-dimensional arrays of chains of gold atoms on a vicinal silicon surface

Abstract

The temperature dependence of electrical conductivity of quasi-one-dimensional arrays of metallic chains formed on a vicinal silicon surface, Si(553)-Au, was measured by a microscopic four-point probe method. A metal-insulator transition was observed around $160\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, which was expected from the previously observed charge density wave formation at low temperatures. This behavior was completely different from that of Si(557)-Au showing an insulating character only. Although both surfaces have similar atomic and electronic structures, differences in interchain coupling and defect density may explain the difference. Inevitably introduced point defects on the surfaces block conduction along the atomic chains. However, with enough interchain coupling, current can flow by avoiding the defects and moving to the adjacent chains on the Si(553)-Au, while it is almost prohibited on the Si(557)-Au due to smaller interchain coupling.