Journal ArticleDOI
Theory of the scanning tunneling microscope
Jerry Tersoff,D. R. Hamann +1 more
TLDR
In this paper, a metal tip is scanned along the surface while ad justing its height to maintain constant vacuum tunneling current, and a contour map of the surface is generated.Abstract:
The recent development of the “scanning tunneling microscope” (STM) by Binnig et al. [8.1–5] has made possible the direct real-space imaging of surface topography. In this technique, a metal tip is scanned along the surface while ad justing its height to maintain constant vacuum tunneling current. The result is essentially a contour map of the surface. This contribution reviews the the ory [8.6–8] of STM, with illustrative examples. Because the microscopic structure of the tip is unknown, the tip wave functions are modeled as s-wave functions in the present approach [8.6, 7]. This approximation works best for small effective tip size. The tunneling current is found to be proportional to the surface local density of states (at the Fermi level), evaluated at the position of the tip. The effective resolution is roughly [2A(R+d)]1/2, where R is the effective tip radius and d is the gap distance. When applied to the 2x1 and 3x1 reconstructions of the Au(l10) surface, the theory gives excellent agreement with experiment [8.4] if a 9 A tip radius is assumed. For dealing with more complex or aperiodic surfaces, a crude but convenient calculational technique based on atom charge superposition is introduced; it reproduces the Au(l10) results reasonably well. This method is used to test the structure-sensitivity of STM. The Au(l10) image is found to be rather insensitive to the position of atoms beyond the first atomic layer.read more
Citations
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Journal ArticleDOI
QUANTUM ESPRESSO: a modular and open-source software project for quantum simulations of materials
Paolo Giannozzi,Stefano Baroni,Stefano Baroni,Nicola Bonini,Matteo Calandra,Roberto Car,Carlo Cavazzoni,Davide Ceresoli,Guido L. Chiarotti,Matteo Cococcioni,Ismaila Dabo,Andrea Dal Corso,Andrea Dal Corso,Stefano de Gironcoli,Stefano de Gironcoli,Stefano Fabris,Stefano Fabris,Guido Fratesi,Ralph Gebauer,Ralph Gebauer,Uwe Gerstmann,Christos Gougoussis,Anton Kokalj,Michele Lazzeri,Layla Martin-Samos,Nicola Marzari,Francesco Mauri,Riccardo Mazzarello,Stefano Paolini,Alfredo Pasquarello,Lorenzo Paulatto,Lorenzo Paulatto,Carlo Sbraccia,Sandro Scandolo,Sandro Scandolo,Gabriele Sclauzero,Gabriele Sclauzero,Ari P. Seitsonen,Alexander Smogunov,Paolo Umari,Renata M. Wentzcovitch +40 more
TL;DR: QUANTUM ESPRESSO as discussed by the authors is an integrated suite of computer codes for electronic-structure calculations and materials modeling, based on density functional theory, plane waves, and pseudopotentials (norm-conserving, ultrasoft, and projector-augmented wave).
Journal ArticleDOI
The Atomic Simulation Environment - A Python library for working with atoms
Ask Hjorth Larsen,Ask Hjorth Larsen,Jens Jørgen Mortensen,Jakob Blomqvist,Ivano E. Castelli,Rune Christensen,Marcin Dulak,Jesper Friis,Michael N. Groves,Bjørk Hammer,Cory Hargus,Eric D. Hermes,Paul C. Jennings,Peter Bjerre Jensen,James R. Kermode,John R. Kitchin,Esben L. Kolsbjerg,Joseph Kubal,Kristen Kaasbjerg,Steen Lysgaard,Jon Bergmann Maronsson,Tristan Maxson,Thomas Olsen,Lars Pastewka,Andrew A. Peterson,Carsten Rostgaard,Jakob Schiøtz,Ole Schütt,Mikkel Strange,Kristian Sommer Thygesen,Tejs Vegge,Lasse B. Vilhelmsen,Michael Walter,Zhenhua Zeng,Karsten Wedel Jacobsen +34 more
TL;DR: The atomic simulation environment (ASE) provides modules for performing many standard simulation tasks such as structure optimization, molecular dynamics, handling of constraints and performing nudged elastic band calculations.
Journal ArticleDOI
First-principles calculations for point defects in solids
Christoph Freysoldt,Blazej Grabowski,Tilmann Hickel,Jörg Neugebauer,Georg Kresse,Anderson Janotti,Chris G. Van de Walle +6 more
TL;DR: The theoretical modeling of point defects in crystalline materials by means of electronic-structure calculations, with an emphasis on approaches based on density functional theory (DFT), is reviewed in this paper.
Journal ArticleDOI
Scanning tunneling microscopy observations on the reconstructed Au(111) surface: Atomic structure, long-range superstructure, rotational domains, and surface defects
TL;DR: Spectroscopy and spin-Polarized STM Reference LNS-ARTICLE-1990-002 provide new insights into the determinants of spin- polarization in the Higgs boson.
Journal ArticleDOI
Buckled silicene formation on Ir(111).
Lei Meng,Yeliang Wang,Lizhi Zhang,Shixuan Du,Rongting Wu,Linfei Li,Yi Zhang,Geng Li,Haitao Zhou,Werner A. Hofer,Hong-Jun Gao +10 more
TL;DR: This work provides a method to fabricate high-quality silicene and an explanation for the formation of the buckled silicenes sheet.
References
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Journal ArticleDOI
Surface studies by scanning tunneling microscopy
TL;DR: In this paper, surface microscopy using vacuum tunneling has been demonstrated for the first time, and topographic pictures of surfaces on an atomic scale have been obtained for CaIrSn 4 and Au.
Journal ArticleDOI
Theory and Application for the Scanning Tunneling Microscope
Jerry Tersoff,D. R. Hamann +1 more
TL;DR: In this article, a theory for vacuum tunneling between a real solid surface and a model probe with a locally spherical tip is presented, applicable to the recently developed "scanning tunneling microscope."
Journal ArticleDOI
Tunneling through a controllable vacuum gap
TL;DR: In this article, the first successful tunneling experiment with an externally and reproducibly adjustable vacuum gap is reported, based on the exponential dependence of the tunneling resistance on the width of the gap.
Journal ArticleDOI
7 × 7 Reconstruction on Si(111) Resolved in Real Space
TL;DR: In this paper, a modified adatom model with 12 adatoms per unit cell and an inhomogeneously relaxed underlying top layer was used for Si(111) reconstruction.
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