Conductivity of Si(111) - 7 x 7: the role of a single atomic step

Abstract

The Si(111) - 7 x 7 surface is one of the most interesting semiconductor surfaces because of its complex reconstruction and fascinating electronic properties. While it is known that the Si - 7 x 7 is a conducting surface, the exact surface conductivity has eluded consensus for decades as measured values differ by 7 orders of magnitude. Here we report a combined STM and transport measurement with ultra-high spatial resolution and minimal interaction with the sample, and quantitatively determine the intrinsic conductivity of the Si - 7 x 7 surface. This is made possible by the capability of measuring transport properties with or without a single atomic step between the measuring probes: we found that even a single step can reduce the surface conductivity by two orders of magnitude. Our first principles quantum transport calculations confirm and lend insight to the experimental observation.

arXiv comment7 pages (main text+EPAPS), 5 figures

Cited by in corpus (8)

• Surface and Step Conductivities on Si(111) Surfaces
• Enhancement and termination of the superconducting proximity effect due to atomic-scale defects visualized by scanning tunneling microscopy
• Scanning tunneling potentiometry implemented into a multi-tip setup by software
• Surface Conductivity of Si(100) and Ge(100) Surfaces Determined from Four-Point Transport Measurements Using an Analytical N-Layer Conductance Model
• Low-Temperature Insulating Phase of the Si(111)--7$\times$7 Surface
• Four-point probe measurements using current probes with voltage feedback to measure electric potentials
• Appearance of effective surface conductivity - an experimental and analytic study
• Nanoscale tip positioning with a multi-tip scanning tunneling microscope using topography images