<i>Ab initio</i>molecular dynamics on the Ge(100) surface

Needels, M.; Payne, M. C.; Joannopoulos, J. D.

doi:10.1103/physrevlett.58.1765

Cited by 156 publications

(52 citation statements)

References 16 publications

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“…Calculations and experimental results have demonstrated that tilting the dimer bonds in various patterns reduces the total surface energy. For Ge, calculations reveal that the c͑4 ϫ 2͒ reconstruction, in which the dimer bond tilts alternate along and perpendicular to the dimer rows, and the p͑2 ϫ 2͒ reconstruction, in which dimer bond tilts alternate only perpendicular to the dimer rows, lie extremely close in energy, [19][20][21] and thus both reconstructions are expected to be observed at finite temperature.…”

Section: Introductionmentioning

confidence: 99%

Surface energetics and structure of the Ge wetting layer on Si(100)

2004

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Ge deposited on Si(100) initially forms heteroepitaxial layers, which grow to a critical thickness of ϳ3 MLs before the appearance of three-dimensional strain relieving structures. Experimental observations reveal that the surface structure of this Ge wetting layer is a dimer vacancy line (DVL) superstructure of the unstrained Ge(100) dimer reconstruction. In the following, the results of first-principles calculations of the thickness dependence of the wetting layer surface excess energy for the c͑4 ϫ 2͒ and 4 ϫ 6 DVL surface reconstructions are reported. These results predict a wetting layer critical thickness of ϳ3 MLs, which is largely unaffected by the presence of dimer vacancy lines. The 4 ϫ 6 DVL reconstruction is found to be thermodynamically stable with respect to the c͑4 ϫ 2͒ structure for wetting layers at least 2 ML thick. A strong correlation between the fraction of total surface induced deformation present in the substrate and the thickness dependence of wetting layer surface energy is also shown.

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Section: Introductionmentioning

confidence: 99%

Surface energetics and structure of the Ge wetting layer on Si(100)

2004

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“…98 The calculated dimer lengths range from 2.38 to 2.51Å and buckling angles are in the range of 19-20 • , which is also in good agreement with the experimentally reported values. 107,[127][128][129] Finally, despite the vanishing band gap for bulk Ge, the existing gap states for the Ge(001) surface reconstructions are qualitatively present in calculated density of states (DOS). 130 …”

Section: A Electronic Structure Calculations: Density Functional Theorymentioning

confidence: 99%

Modeling 1D structures on semiconductor surfaces: synergy of theory and experiment

Vanpoucke

2014

J. Phys.: Condens. Matter

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Atomic scale nanowires attract enormous interest in a wide range of fields. On the one hand, due to their quasi-one-dimensional nature, they can act as a experimental testbed for exotic physics: Peierls instability, charge density waves, and Luttinger liquid behavior. On the other hand, due to their small size, they are of interest for future device applications in the micro-electronics industry, but also for applications regarding molecular electronics. This versatile nature makes them interesting systems to produce and study, but their size and growth conditions push both experimental production and theoretical modeling to their limits. In this review, modeling of atomic scale nanowires on semiconductor surfaces is discussed focusing on the interplay between theory and experiment. The current state of modeling efforts on Pt-and Au-induced nanowires on Ge (001) is presented, indicating their similarities and differences. Recently discovered nanowire systems (Ir, Co, Sr) on the Ge(001) surface are also touched upon. The importance of scanning tunneling microscopy as a tool for direct comparison of theoretical and experimental data is shown, as is the power of density functional theory as an atomistic simulation approach. It becomes clear that complementary strengths of theoretical and experimental investigations are required for successful modeling of the atomistic nanowires, due to their complexity.

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“…Nevertheless, a commonly accepted picture of the reconstructed Ge͑001͒ surface consists of an asymmetric dimer ordering in a (2x1) structure at room temperature (RT), while the surface reconstructs according to a c͑4 ϫ 2͒ arrangement at low temperature. In addition, Needels et al 17,18 found the c͑4 ϫ 2͒ and p͑2 ϫ 2͒ reconstructions are almost degenerate and their energy is approximately 0.07 eV per dimer lower than that of the b͑2 ϫ 1͒ structure. They also suggested the existence of a phase transition at 380± 100 K, between the ordered c͑4 ϫ 2͒ or p͑2 ϫ 2͒ state and the disordered b͑2 ϫ 1͒ state.…”

Section: A Ge"001… 2ã 1 Surfacementioning

confidence: 99%

“…The symmetric versus asymmetric nature of the dimer bond has been an important issue for both theoretical and experimental investigations. Many theoretical [16][17][18] and experimental 19 works have favored the asymmetric dimers. Besides, in addition to the buckled b͑2 ϫ 1͒, higher order reconstructions of Ge͑001͒ surface, such as c͑4 ϫ 2͒ or p͑2 ϫ 2͒ have been observed.…”

Section: A Ge"001… 2ã 1 Surfacementioning

confidence: 99%

Initial stages ofPtgrowth onGe(001)studied by scanning tunneling microscopy and density functional theory

et al. 2004

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We have studied the initial stages of submonolayer Pt growth on the Ge͑001͒. We have observed several stable and meta-stable adsorption configurations of Pt atoms at various temperatures. Calculations indicate relatively high binding energies of Pt atoms onto the Ge lattice, at different adsorption sites. Our results show that through-the-substrate bonding (concerted bonding) of two Pt atoms is more favored on Ge͑001͒ surface then a direct Pt-Pt bond. Both our experiments and calculations indicate the breaking of Ge-Ge bonds on the surface in the vicinity of Pt adsorbates. We have also observed the spontaneous generation of 2 + 1 dimer vacancy defects at room temperature that cause the ejection of Ge atoms onto the surface. Finally we have studied the diffusion of Pt atoms into the bulk as a result of annealing and found out that they get trapped at subsurface sites.

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Ab initiomolecular dynamics on the Ge(100) surface

Cited by 156 publications

References 16 publications

Surface energetics and structure of the Ge wetting layer on Si(100)

Surface energetics and structure of the Ge wetting layer on Si(100)

Modeling 1D structures on semiconductor surfaces: synergy of theory and experiment

Initial stages ofPtgrowth onGe(001)studied by scanning tunneling microscopy and density functional theory

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