Quasi-one-dimensional metals on semiconductor surfaces with defects

Abstract

Several examples are known in which massive arrays of metal atomic chains are formed onsemiconductor surfaces that show quasi-one-dimensional metallic electronic structures. Inthis review, Au chains on Si(557) and Si(553) surfaces, and In chains on Si(111) surfaces,are introduced and discussed with regard to the physical properties determined byexperimental data from scanning tunneling microscopy (STM), angle-resolvedphotoemission spectroscopy (ARPES) and electrical conductivity measurements. Theyshow quasi-one-dimensional Fermi surfaces and parabolic band dispersion along the chains.All of them are known from STM and ARPES to exhibit metal–insulator transitionsby cooling and charge-density-wave formation due to Peierls instability of themetallic chains. The electrical conductivity, however, reveals the metal–insulatortransition only on the less-defective surfaces (Si(553)–Au and Si(111)–In), butnot on a more-defective surface (Si(557)–Au). The latter shows an insulatingcharacter over the whole temperature range. Compared with the electronic structure(Fermi surfaces and band dispersions), the transport property is more sensitiveto the defects. With an increase in defect density, the conductivity only alongthe metal atomic chains was significantly reduced, showing that atomic-scalepoint defects decisively interrupt the electrical transport along the atomic chainsand hide the intrinsic property of transport in quasi-one-dimensional systems.