AVS 47th International Symposium
    Processing at the Nanoscale/NANO 6 Wednesday Sessions
       Session NS+NANO6-WeA

Paper NS+NANO6-WeA8
Conductance Anisotropy in a Mesoscopic Array of Atomic Wires: Ga/Si(112)@footnote 1@

Wednesday, October 4, 2000, 4:20 pm, Room 302

Session: Nanoscale Modification of Materials
Presenter: K.J. Yoo, University of Tennessee
Authors: K.J. Yoo, University of Tennessee
S. Tang, University of Tennessee
P.T. Sprunger, Louisiana State University
H.H. Weitering, University of Tennessee
Correspondent: Click to Email
In recent years, researchers at the Naval Research Laboratory have used the Si(112) surface as a template for the fabrication of a mesoscopic array of single-atom-wide gallium wires or quantum wires.@footnote 2@ The structural uniformity of the wire array appears far superior to those created by nanolithographic methods. We have characterized this Ga/Si(112) hetero-structure with Scanning Tunneling Microscopy, Angle-Resolved Photoelectron Spectroscopy (ARPES), and Si 2p core-level spectroscopy. The electrical conductivity of the wire-array was measured as a function of temperature in ultrahigh vacuum using the four-point-probe technique parallel and perpendicular to the quantum wires. The parallel conductivity has a temperature-dependence characteristic of a semiconductor. In contrast, the conductivity perpendicular to the wires appears metallic. This unexpected result can be understood on the basis of first-principles calculations by Flores and coworkers in Madrid @footnote 3@, which indicate that the band effective mass in the perpendicular direction is close to the free electron mass (m*=1.3 m@sub e@) whereas the effective mass in the parallel direction is very large (m*> 5.5 m@sub e@). The main features of the theoretical surface-state band structure have been confirmed with ARPES. Contributions to the electrical conductivity by the space charge layer beneath the surface have been calculated based on core level measurements of band bending. These contributions were subtracted to determine the electrical conductance solely through the quantum wires. @FootnoteText@ @footnote 1@Work supported by National Science Foundation(DMR-9705246). @footnote 2@A. A. Baski, S. C. Erwin, and L. J. Whitman, J. Vac. Sci., B14(2), 992(1996). @footnote 3@F. Flores, in private communication.