Metallic transport in a monatomic layer of in on a silicon surface.

Department of Physics, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Physical Review Letters (Impact Factor: 7.73). 03/2011; 106(11):116802. DOI: 10.1103/PhysRevLett.106.116802
Source: PubMed

ABSTRACT We have succeeded in detecting metallic transport in a monatomic layer of In on an Si(111) surface, Si(111)-sqrt[7]×sqrt[3]-In surface reconstruction, using the micro-four-point probe method. The In layer exhibited conductivity higher than the minimum metallic conductivity (the Ioffe-Regel criterion) and kept the metallic temperature dependence of resistivity down to 10 K. This is the first example of a monatomic layer, with the exception of graphene, showing metallic transport without carrier localization at cryogenic temperatures. By introducing defects on this surface, a metal-insulator transition occurred due to Anderson localization, showing hopping conduction.

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    ABSTRACT: tSi(1 1 1)–In surface reconstructions for submonolayer coverages were investigated at room temperatureusing X-ray photoelectron spectroscopy, Auger electron spectroscopy and low-energy electron diffrac-tion. Deposition rate influence on the formation of surface structures is reported. It was observed that forsufficiently low deposition rate and certain annealing process Si(1 1 1)√7 ×√3–In surface reconstructionat coverage as low as 0.2 ML is present.
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    ABSTRACT: In/Si(111) surfaces have a variety of phases, among which 4× 1 and \sqrt{7}×\sqrt{3} show intriguing one-/two-dimensional (1D/2D) electronic properties. Here, we carry out extensive experiments to investigate the mechanical properties of various phases on the surfaces by atomic force microscopy at room temperature. Energy dissipation associated with flexibility is measured at the atomic scale. In the 4× 1 phase, dissipation locally increases at the inner parts of couples of In chains, which correspond to mobile In atoms in a dynamical fluctuation model for the phase transition. An extremely large dissipation signal is obtained on the \sqrt{7}×\sqrt{3} phase, indicating that a single atomic layer of In is weakly attached to the Si substrate, which is consistent with the 2D electronic properties.
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