Article

Metallic Transport in a Monatomic Layer of In on a Silicon Surface

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Department of Physics, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
(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
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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. "
Article: Low coverage Si(1 1 1)√7 ×√3–In reconstruction:Deposition rate effect
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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.
Full-text · Article · Mar 2014 · Applied Surface Science
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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. "
Article: Resistive phase transition of the superconducting Si(111)-(7×3)-In surface
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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.
Full-text · Article · Apr 2013 · Nanoscale Research Letters
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Article: Effect of the stoichiometric composition of the Si(111)√21 × √21-(Au, Ag) surface phase on substrate conductivity
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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.
Full-text · Article · Jun 2013 · Semiconductors
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