Presentation Information
[2G07]Role of semiconducting nanoregion on macroscopic transport properties studied by scanning tunneling microscopy/spectroscopy/potentiometry
*Masahiro Haze1, Junya Okazaki1, Masayuki Hamada1, Yukio Hasegawa1 (1. Institute for Solid State Physics, University of Tokyo)
Electrical transport measurements are a fundamental approach for characterizing materials. However, they generally lack the ability to resolve local properties. In this study, we investigated the relationship between the transport properties and atomic structures in Pb monolayers formed on Si(111), using low-temperature scanning tunneling microscopy (STM), combined with scanning tunneling potentiometry (STP). STM measurements revealed that the terraces are predominantly covered by a metallic √7 × √3 phase, while the step edges exhibit defect-rich 3 × 3 structures, which are found to be semiconducting by STS. STP measurements revealed significant potential drops at these step edges, indicating that the semiconducting regions at the steps are the major source of resistance. Additionally, we found that the potential drops were negligible across the steps bridged by the metallic Pb islands. These findings underscore the crucial role of local nanoscale structures in governing the transport properties in ultrathin two-dimensional systems.