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: 7.51). 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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Available from: Yukio Hasegawa, Sep 28, 2015
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    • ". However, despite the fact that the phase diagram for positive temperatures in Celsius scale and coverages up to 1 ML was presented as early as in 1979 [4], the system is constantly being studied and it seems that some observations still remain unclear. Of particular interest are atomic models for those structures [5] [6] [7] [8] and the nature of In-covered Si surfaces [9] [10]. One of the very interesting phases which was widely studied in 1990s [3] [11] is the √ 7 × √ 3 structure. "
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    ABSTRACT: Si(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.
    Applied Surface Science 03/2014; 304:103-106. DOI:10.1016/j.apsusc.2014.03.063 · 2.71 Impact Factor
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    • ")-In surface was prepared by thermal evaporation of In onto a clean Si(111) substrate, followed by annealing at around 300°C for approximately 10 s in UHV [18-20], and was subsequently confirmed by low-energy electron diffraction and STM. The sample was then patterned by Ar + sputtering through a shadow mask to define the current path for four-terminal resistance measurements. "
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    ABSTRACT: Recently, superconductivity was found on semiconductor surface reconstructions induced by metal adatoms, promising a new field of research where superconductors can be studied from the atomic level.Here we measure the electron transport properties of the Si(111)-(¿7 × ¿3)-In surface near the resistive phase transition and analyze the data in terms of theories of two-dimensional (2D) superconductors.In the normal state, the sheet resistances (2D resistivities) R¿ of the samples decrease significantly between 20 and 5 K, suggesting the importance of the electron-electron scattering in electron transport phenomena.The decrease in R¿ is progressively accelerated just above the transition temperature (Tc) due to the direct (Aslamazov-Larkin term) and the indirect (Maki-Thompson term) superconducting fluctuation effects.A minute but finite resistance tail is found below Tc down to the lowest temperature of 1.8 K, which may be ascribed to a dissipation due to free vortex flow.The present study lays the ground for a future research aiming to find new superconductors in this class of materials.
    Nanoscale Research Letters 04/2013; 8(1):167. DOI:10.1186/1556-276X-8-167 · 2.78 Impact Factor
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    ABSTRACT: The conductivity of a silicon substrate with a Si(111) $\sqrt {21} $ × $\sqrt {21} $ -(Au, Ag) surface phase is studied. It is found that the surface conductivity of such a substrate varies depending on the ratio of the amounts of gold and silver in the given structure. An analysis of the behavior of the Si(111) $\sqrt {21} $ × $\sqrt {21} $ -(Au, Ag) surface conductivity during silver adsorption indicates the effect of a space-charge layer in the surface region of the substrate on the measurement results.
    Semiconductors 06/2013; 47(6). DOI:10.1134/S1063782613060298 · 0.74 Impact Factor
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