title: Electron Transport Suppression from Tip-π State Interaction on Si(100)-2 × 1 Surfaces.
abstract: We investigate the electron transport between a scanning tunneling microscope tip and Si(100)-2 × 1 surfaces with four distinct configurations by performing calculations using density functional theory and the nonequilibrium Green's function method. Interestingly, we find that the conducting mechanism is altered when the tip-surface distance varies from large to small. At a distance larger than the critical value of 4.06 Å, the conductance is increased with a reduction in distance owing to the π state arising from the silicon dimers immediately under the tip; this in turn plays a key role in facilitating a large transmission probability. In contrast, when the tip is closer to the substrate, the conductance is substantially decreased because the π state is suppressed by the interaction with the tip, and its contribution in the tunneling channels is considerably reduced.
authors.affiliation: School of Physics, Shandong University, Jinan 250100, P.R. China.|Nano-organic Photoelectronic Laboratory, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: K P
authors.initials: KP
authors.lastname: Dou
authors.affiliation: Nano-organic Photoelectronic Laboratory, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: W
authors.initials: W
authors.lastname: Fan
authors.affiliation: Institute I-Theoretical Physics, University of Regensburg, D-93040 Regensburg, Germany.|Bremen Center for Computational Material Science, University Bremen, 28334 Bremen, Germany.
authors.forename: T A
authors.initials: TA
authors.lastname: Niehaus
authors.affiliation: Bremen Center for Computational Material Science, University Bremen, 28334 Bremen, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Frauenheim
authors.affiliation: School of Physics, Shandong University, Jinan 250100, P.R. China.
authors.forename: C L
authors.initials: CL
authors.lastname: Wang
authors.affiliation: Nano-organic Photoelectronic Laboratory, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: X H
authors.initials: XH
authors.lastname: Zhang
authors.affiliation: Center of Super-Diamond and Advanced Films and Department of Physics and Materials Science, City University of Hong Kong, Hong Kong Special Administrative Region, China.
authors.forename: R Q
authors.initials: RQ
authors.lastname: Zhang