title: Surface and Step Conductivities on Si(111) Surfaces.
abstract: Four-point measurements using a multitip scanning tunneling microscope are carried out in order to determine surface and step conductivities on Si(111) surfaces. In a first step, distance-dependent four-point measurements in the linear configuration are used in combination with an analytical three-layer model for charge transport to disentangle the 2D surface conductivity from nonsurface contributions. A termination of the Si(111) surface with either Bi or H results in the two limiting cases of a pure 2D or 3D conductance, respectively. In order to further disentangle the surface conductivity of the step-free surface from the contribution due to atomic steps, a square four-probe configuration is applied as a function of the rotation angle. In total, this combined approach leads to an atomic step conductivity of σ(step)=(29±9)  Ω(-1) m(-1) and to a step-free surface conductivity of σ(surf)=(9±2)×10(-6)  Ω(-1)/□ for the Si(111)-(7×7) surface.
authors: Peter Grünberg Institut (PGI-3) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich, Germany.
authors: Sven
authors: S
authors: Just
authors: Peter Grünberg Institut (PGI-3) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich, Germany.
authors: Marcus
authors: M
authors: Blab
authors: Peter Grünberg Institut (PGI-3) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich, Germany.
authors: Stefan
authors: S
authors: Korte
authors: Peter Grünberg Institut (PGI-3) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich, Germany.
authors: Vasily
authors: V
authors: Cherepanov
authors: Central Institute of Engineering, Electronics and Analytics (ZEA-1), Forschungszentrum Jülich, 52425 Jülich, Germany.
authors: Helmut
authors: H
authors: Soltner
authors: Peter Grünberg Institut (PGI-3) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich, Germany.
authors: Bert
authors: B
authors: Voigtländer