Impurity-induced changes of overlayer symmetry and of phase transitions

Godzik, G.; Pfnür, H.; Lyuksyutov, I. F.

doi:10.1209/epl/i2001-00488-0

Cited by 12 publications

(6 citation statements)

References 19 publications

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“…Indeed such modifications have been observed by doping these layers with concentrations of oxygen much less than one atom per unit cell. 19 This corroborates the model for the effective chain interactions qualitatively. A detailed description of these modifications for the structures discussed here will be presented elsewhere.…”

Section: ͑2͒supporting

confidence: 82%

Depinning transitions between adsorbate chains coupled by Friedel oscillations

2003

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The low coverage phase transitions of the p(8ϫ1) and the p(5ϫ1) chain structures of the Sr/Mo͑112͒ system have been investigated with low-energy electron diffraction ͑LEED͒ at constant coverages. It turns out that both structures show similar physics. They first undergo depinning phase transitions at temperatures just below 100 K into striped domain wall structures. The domain wall lattice shows continuous melting at temperatures between 197 and 218 K. Coupling between the adsorbate chains can be described by the potential created by adsorbate-induced charge density waves involving surface states. Within this model domain wall formation appears as thermal excitation of stacking faults on a discrete lattice. For the p(5ϫ1) structure, domain wall formation energies of approximately 65 and 38 meV have been derived for heavy and light walls, respectively, from a fit to the experimental data of depinning.

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Section: ͑2͒supporting

confidence: 82%

Depinning transitions between adsorbate chains coupled by Friedel oscillations

2003

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“…This, however, can be easily transformed with small amounts of oxygen impurities into a stable domain of p͑2 ϫ 1͒ structures. 34 The role played by the irregularly distributed O doping is difficult to quantify in this type of calculations and is deferred to a future study. Our calculations show ( Table II) that the c͑2 ϫ 2͒ structure is by 20 meV more stable than the p͑2 ϫ 1͒.…”

Section: Low-coverage Sr Structuresmentioning

confidence: 99%

Energetics ofSradatom interactions on theMo(112)surface

Kiejna

Nieminen

2004

Phys. Rev. B

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First-principles methods are used to investigate the formation and structure of the ordered phases of Sr atoms adsorbed on the furrowed Mo͑112͒ surface. The energetics of various commensurate and incommensurate adatom structures providing information on lateral interactions between adatoms is determined for coverages 0.11ഛ⌰ഛ1 monolayer. It is found that the binding energy of Sr atoms decreases with increasing coverage. The experimentally observed p͑8 ϫ 1͒ and p͑5 ϫ 1͒ adatom chains are found to belong to the most favored structures for ⌰Ͻ0.5. The energetic difference between these two structures amounts to 20 meV. The experimental work function variation with Sr adatom coverage is very well reproduced. The energy barriers for Sr diffusion along the atomic troughs are calculated and discussed.

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“…In most cases, an adsorbed impurity causes point defects and changes the crystal structure locally. However, it is also possible to restructure the whole surface with a different preferred orientation 15…”

Section: Introductionmentioning

confidence: 99%