Université de Fribourg

Structure and stability of the Si(331)-(12×1) surface reconstruction investigated with first-principles density functional theory

Battaglia, Corsin ; Onida, Giovanni ; Gaál-Nagy, Katalin ; Aebi, Philipp

In: Physical Review B: condensed matter and materials physics, 2009, vol. 80, no. 21, p. 214102

We recently proposed a structural model for the Si(331)-(12×1) surface reconstruction containing silicon pentamers and adatoms as elementary structural building blocks. Using first-principles density functional theory we here investigate the stability of a variety of adatom configurations and determine the lowest-energy configuration. We also present a detailed comparison of the energetics...

Université de Fribourg

Valence band structure of the Si(331)-(12 × 1) surface reconstruction

Battaglia, Corsin ; Schwier, Eike Fabian ; Monney, Claude ; Didiot, Clément ; Mariotti, Nicolas ; Gaál-Nagy, Katalin ; Onida, Giovanni ; Garnier, Michael Gunnar ; Aebi, Philipp

In: Journal of Physics: Condensed Matter, 2011, vol. 23, no. 13, p. 135003

Using angle-resolved photoelectron spectroscopy we investigate the electronic valence band structure of the Si(331)-(12 × 1) surface reconstruction for which we recently proposed a structural model containing silicon pentamers as elementary structural building blocks. We find that this surface, reported to be metallic in a previous study, shows a clear band gap at the Fermi energy, indicating...

Université de Fribourg

Evolution of the charge density wave superstructure in ${\mathrm{ZrTe}}_{3}$ under pressure

Hoesch, Moritz ; Garbarino, Gaston ; Battaglia, Corsin ; Aebi, Philipp ; Berger, Helmuth

In: Physical Review B, 2016, vol. 93, no. 12, p. 125102

The material ZrTe3 is a well-known example of an incommensurate periodic lattice distortion (PLD) at low temperatures due to a charge density wave (CDW). Previous studies have found a sharp boundary as a function of pressure between CDW below 5 GPa and bulk superconductivity above this value. We present a study of low-temperature-high-pressure single crystal x-ray diffraction along with ab initio...

Université de Fribourg

Quasi one-dimensional Ag nanostructures on Si(331)–(12 × 1)

Mariotti, Nicolas ; Didiot, Clément ; Schwier, Eike Fabian ; Monney, Claude ; Battaglia, Corsin ; Aebi, Philipp

In: Surface Science, 2015, vol. 639, p. 39-42

We report on the deposition of sub-monolayer Ag on the Si(331)–(12 × 1) surface. The growth of one-dimensional Ag nanostructures is observed by means of low- temperature scanning tunneling microscopy and low energy electron diffraction. We find that the deposited Ag is organized in nanostructures consistently taking “sawtooth” shapes. While the structures are not perfectly organized,...

Université de Fribourg

Scanning tunneling microscopy at multiple voltage biases of stable “ring-like” Ag clusters on Si(111)–(7 × 7)

Mariotti, Nicolas ; Didiot, Clément ; Schwier, Eike Fabian ; Monney, Claude ; Perret-Aebi, Laure-Emmanuelle ; Battaglia, Corsin ; Garnier, M.G. ; Aebi, Philipp

In: Surface Science, 2012, vol. 606, no. 23-24, p. 1755-1759

Since more than twenty years it is known that deposition of Ag onto Si(111)–(7 × 7) leads under certain conditions to the formation of so-called “ring-like” clusters, that are particularly stable among small clusters. In order to resolve their still unknown atomic structure, we performed voltage dependent scanning tunneling microscopy (STM) measurements providing interesting...

Université de Fribourg

Temperature dependence of the excitonic insulator phase model in 1T-TiSe₂

Monney, Claude ; Cercellier, H. ; Battaglia, Corsin ; Schwier, Eike Fabian ; Didiot, Clément ; Garnier, M.G. ; Beck, Hans ; Aebi, Philipp

In: Physica B: Condensed Matter, 2009, vol. 404, no. 19, p. 3172-3175

Recently, detailed calculations of the excitonic insulator phase model adapted to the case of 1T-TiSe2 have been presented. Through the spectral function theoretical photoemission intensity maps can be generated which are in very good agreement with experiment [H. Cercellier, et al., Phys. Rev. Lett. 99 (2007) 146403]. In this model, excitons condensate in a BCS-like manner and give rise to a...

Université de Fribourg

Exciton Condensation Driving the Periodic Lattice Distortion of 1T-TiSe₂

Monney, Claude ; Battaglia, Corsin ; Cercellier, H. ; Aebi, Philipp ; Beck, Hans

In: Physical Review Letters, 2011, vol. 106, no. 10, p. 106404

We address the lattice deformation of 1T-TiSe₂ within the exciton condensate phase. We show that, at low temperature, condensed excitons influence the lattice through electron-phonon interaction. It is found that at zero temperature, in the exciton condensate phase of 1T-TiSe₂, this exciton condensate exerts a force on the lattice generating ionic displacements comparable in amplitude to what...