Atomic Structure of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="italic">c</mml:mi></mml:math>(<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mn>4</mml:mn><mml:mo>×</mml:mo><mml:mn>2</mml:mn></mml:math>) Surface Reconstruction of Ge(001) as Determined by X-Ray Diffraction

Ferrer, S.; Torrelles, X.; Etgens, V. H.; Vegt, H.A. van der; Fajardo, P.

doi:10.1103/physrevlett.75.1771

Cited by 85 publications

(42 citation statements)

References 15 publications

(21 reference statements)

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“…The bare Si(0 0 1) surface exhibits c(4 Â 2) and p(2 Â 2) reconstructions at low temperatures and the (2 Â 1) reconstruction at room temperature, which is characterized by the Si-Si dimer formation as the building block, is well studied, both theoretically [25][26][27] and experimentally [30][31][32]. Recent theoretical work calculated the alternating (semi-antiphase) dimer (2 Â 2) reconstruction is favorable than the (1 Â 2) phase by approximately 0.24 eV/ dimer [27].…”

Section: Resultsmentioning

confidence: 99%

Atomic and electronic properties of furan on the Si(001)-(2×2) surface

et al. 2008

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Section: Resultsmentioning

confidence: 99%

Atomic and electronic properties of furan on the Si(001)-(2×2) surface

et al. 2008

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“…Moreover, the lattice is further stabilized by a distinct buckling pattern of the surface dimers, which leads to a c͑4 ϫ 2͒ superstructure at low temperatures. DFT-based structure optimization has fully reproduced x-ray diffraction data for the clean Ge͑001͒ surface 30,31 and, in addition, showed a good agreement for the resulting surface electronic states. 32 We simulate the Ge͑001͒ surface by means of repeated asymmetric slabs of eight Ge layers and a vacuum region of the same size.…”

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confidence: 75%

First-principles description of atomic gold chains on Ge(001)

et al. 2010

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We have performed density-functional theory calculations, including the spin-orbit correction, to investigate atomic gold chains on Ge͑001͒. A set of 26 possible configurations of the Au/Ge͑001͒ system with c͑4 ϫ 2͒ and c͑8 ϫ 2͒ symmetries is studied. Our data show that the c͑4 ϫ 2͒ order results in the lowest energy, which is not in direct agreement with recent experiments. Using total-energy calculations, we are able to explain these differences. We address the electronic band structure and apply the Tersoff-Hamann approach to correlate our data to scanning-tunneling microscopy ͑STM͒. We obtain two highly competitive structures of the atomic Au chains for which we report simulated STM images in order to clarify the composition of the experimental Au/Ge͑001͒ surface. is limited to a chain length of several ten atoms, utilization of self-organization processes of adatoms on surfaces can lead to much longer chains. These chains are of great interest both for basic research and for various applications because they give rise to a ͑quasi-͒ one-dimensional electron system. In this context, Schäfer et al. 5 recently discovered a new system: self-organized atomic Au chains on Ge͑001͒ with a c͑8 ϫ 2͒ long-range order. These Au nanowires appear to be largely decoupled from the Ge substrate and therefore have been put forward as a model system for a Luttinger liquid. [6][7][8] Self-organized In wires on Si͑111͒ ͑Ref. 9͒ and Au wires on Si͑533͒, 10 on the contrary, have been found to exhibit a significant coupling to the substrate. For the Ge͑001͒ surface, Au growth, in general, comes along with a large variety of ordering phenomena as a function of both coverage and growth temperature.11 The Ge͑001͒ surface thereby is subject to a strong relaxation. In particular, a missing-row reconstruction with emerging microfacets of the Ge͑111͒ type, 12 which is known from the clean Au͑110͒, Ir͑110͒, and Pt͑110͒ surfaces, 13,14 has been reported. Adsorption of Pt atoms on Ge͑001͒ results in highly ordered arrays of nanowires, which show very little defects and reach lengths of several 100 nm. 15,16 The latter system has been investigated in detail 17,18 by ab initio calculations based on the density-functional theory ͑DFT͒, 19 demonstrating the capacity of ab initio methods for interpreting experimental data, particularly, from STM and angular-resolved photoelectron spectroscopy. Specifically, the pseudopotential method provides useful information by accurate theoretical STM images, which help to understand experimental data. 20Our findings are based on total-energy DFT calculations in the framework of the projector-augmented wave method, 21,22 using the Vienna ab initio simulation package. 23,24 For the exchange-correlation functional, we apply the generalized gradient approximation and the PerdewBurke-Ernzerhof scheme. 25 All our data have been obtained under the inclusion of the spin-orbit coupling, which is essential for describing the electronic as well as optical properties of Au systems. 26 We use a 250-eV-plane-wave energy c...

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“…This was mainly dictated by the designs of the diffractometers and sample chambers that allowed only limited perpendicular momentum transfer. The more recent diffractometers, however, have extra degrees of freedom © 1997 International Union of Crystallography Printed in Great Britain -all rights reserved (on the detector), enabling a wide range of perpendicular momentum transfer to be reached and thus allowing atomic coordinates to be determined with high accuracy in all three directions (Ferrer, Torrelles, Etgens, Van der Vegt & Fajardo, 1995;Lohmeier et al, 1996). Different geometries for such diffractometers are in use: there are five-circle diffractometers with and without extra detector arms (Vlieg, Van der Veen, Macdonald & Miller, 1987;Taylor, Norris, Vlieg, Lohmeier & Turner, 1996), six-circle diffractometers (Lohmeier & Vlieg, 1993) and so-called (2+2)-circle diffractometers (Evans-Lutterodt & Tang, 1995).…”

Section: Introductionmentioning

confidence: 99%

Integrated Intensities Using a Six-Circle Surface X-ray Diffractometer

Vlieg¹

1997

J Appl Crystallogr

298

267

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The geometrical and resolution corrections are derived that occur in the measurement of the integrated intensities of surface diffraction rods for the case of a sixcircle diffractometer. Since the six-circle geometry entails as special cases the five-circle and the z-axis diffractometers, the results are valid for these geometries as well. The derivations are valid for any incoming or outgoing angle of the X-ray beam, and are particularly important for measurements at large perpendicular momentum transfer. Expressions are derived for the integrated intensity from rocking scans, from stationary measurements and from reflectivity data. With all correction factors known, it is possible to derive the structure factors with a common scale factor from all these types of scans. It is expected that area detectors combined with stationary measurements will find widespread use in the surface X-ray diffraction community.

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Atomic Structure of thec(4×2) Surface Reconstruction of Ge(001) as Determined by X-Ray Diffraction

Cited by 85 publications

References 15 publications

Atomic and electronic properties of furan on the Si(001)-(2×2) surface

Atomic and electronic properties of furan on the Si(001)-(2×2) surface

First-principles description of atomic gold chains on Ge(001)

Integrated Intensities Using a Six-Circle Surface X-ray Diffractometer

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