OF PusSi a y=t Si~ y=0.5 Pu(1 x=O z=0.25 x=0.5 ... Difference Fourier section at z=0.25 for PusSi 3. Contours as in Fig. 1.thus, in ...
Tópico(s): Advanced X-ray Imaging Techniques
1964 - Wiley | Acta Crystallographica
J. D. Fuhr, J. E. Gayone, J. Martínez-Blanco, E. G. Michel, H. Ascolani,
... as the ground state for this surface [K. Pussi, E. Al Shamaileh, E. McLoughin, A. A. Cafolla, ...
Tópico(s): Physics of Superconductivity and Magnetism
2009 - American Physical Society | Physical Review B
H. I. Li, K. Pussi, Kelly Hanna, L.-L. Wang, D. D. Johnson, Hai‐Ping Cheng, H. Shin, Stefano Curtarolo, W. Moritz, J. A. Smerdon, R. McGrath, Renee D. Diehl,
The geometry of adsorbed ${\mathrm{C}}_{60}$ influences its collective properties. We report the first dynamical low-energy electron diffraction study to determine the geometry of a ${\mathrm{C}}_{60}$ monolayer, $\mathrm{Ag}(111)\mathrm{\text{\ensuremath{-}}}(2\sqrt{3}\ifmmode\times\else\texttimes\fi{}2\sqrt{3})30\ifmmode^\circ\else\textdegree\fi{}\mathrm{\text{\ensuremath{-}}}{\mathrm{C}}_{60}$, and related density functional theory calculations. The stable monolayer has ${\mathrm{C}}_{60}$ molecules in ...
Tópico(s): Advanced Chemical Physics Studies
2009 - American Physical Society | Physical Review Letters
K. Pussi, M. Gierer, Renee D. Diehl,
A thin film of copper on the fivefold surface of Al–Pd–Mn forms a structure that is uniaxially commensurate with the aperiodic structure of the substrate. This structure has been analyzed using low-energy electron diffraction and is found to consist of a vicinal surface of a body-centered tetragonal (bct) (100) structure. This bct(100) structure has lattice parameters of a = 2.88 Å, b = 2.55 Å and c = 2.88 Å, with the vicinal surface making an angle α of 13.28° relative to the a–b plane. This structure ...
Tópico(s): X-ray Diffraction in Crystallography
2009 - IOP Publishing | Journal of Physics Condensed Matter
K. Pussi, J. A. Smerdon, Nicola Ferralis, M. Lindroos, R. McGrath, Renee D. Diehl,
Dynamical low-energy electron diffraction (LEED) was used to study the structures of graphite (0 0 0 1) and graphite (0 0 0 1)-(√3×√3)R30°-Xe. Natural single crystals of graphite were used in these studies, and their surface structure was found to be the same as the bulk structure. The adsorbed Xe was found to occupy the hollow sites of the honeycomb substrate at a distance of 3.59 ± 0.04 Å above the graphite plane.
Tópico(s): Crystallography and Radiation Phenomena
2003 - Elsevier BV | Surface Science
K. Pussi, Ehab AlShamaileh, Eilish McLoughlin, A.A. Cafolla, M. Lindroos,
The geometrical structure of 0.50 ML Sn adsorbed on Cu{1 0 0} surface has been studied using Symmetrized Automated Tensor LEED. At this coverage, a p(32×2)R45° ordered surface structure is formed. The favoured structure is a substitutional surface alloy, that includes a missing row reconstruction. This structure might have originated a from c(2 × 2) superstructure. The p(32×2)R45° phase is formed by bringing pairs of Sn atoms together in the Cu{1 0 0}-c(2 × 2)–Sn alloyed top layer and removing every ...
Tópico(s): Copper Interconnects and Reliability
2003 - Elsevier BV | Surface Science
... Erst nach Vereinigung des Versuchstieres mit Artgenossen (Rotfüchsin Pussi am 104. Lebenstag) kam es zur Auslösung dieser ...
Tópico(s): Animal Behavior and Welfare Studies
2010 - Wiley | Zeitschrift für Tierpsychologie
K. H. L. Zhang, I.M. McLeod, Yunhao Lu, V.R. Dhanak, A. Matilainen, M. Lahti, K. Pussi, R.G. Egdell, X.‐S. Wang, Andrew T. S. Wee, Wei Chen,
The atomic structures that develop as a function of coverage during deposition of Bi on Ag(111) have been studied using low-temperature scanning tunneling microscopy, low-energy electron diffraction, and ab initio calculations. The growth process involves two sequential stages. At low coverage, Bi atoms are incorporated into the topmost layer of Ag(111), resulting in the formation of an Ag${}_{2}$Bi alloy confined to the surface and ordered ($\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3}$)$R$30\ ...
Tópico(s): Advanced Chemical Physics Studies
2011 - American Physical Society | Physical Review B
K. Pussi, A. Matilainen, V.R. Dhanak, Aron Walsh, R.G. Egdell, K. H. L. Zhang,
Tópico(s): Electronic and Structural Properties of Oxides
2011 - Elsevier BV | Surface Science
Fiona McBride, George R. Darling, K. Pussi, A. Hodgson,
Recent studies show that structures based on the traditional "icelike" water bilayer are not stable on flat transition metal surfaces and, instead, more complex wetting layers are formed. Here we show that an ordered bilayer can be formed on a SnPt(111) alloy template and determine the structure of the water layer by low energy electron diffraction. Close agreement is found between experiment and the structure calculated by density functional theory. Corrugation of the alloy surface allows only alternate ...
Tópico(s): Advanced Chemical Physics Studies
2011 - American Physical Society | Physical Review Letters
Heekeun Shin, K. Pussi, Émilie Gaudry, J. Ledieu, V. Fournée, Sebastián Alarcón Villaseca, Jean‐Marie Dubois, Yu. Grin, P. Gille, W. Moritz, Renee D. Diehl,
In a combined scanning tunneling microscopy (STM), low-energy electron diffraction (LEED), and density functional theory (DFT) study of the surface of Al${}_{13}$Co${}_{4}$(100), all techniques have found that after annealing to 1165 K, the surface structure is consistent with a dense Al-rich plane with surface Co atom depletion. Various structure models were considered, and in the LEED study, the best agreement was found with a model that consists of Al-rich terminating planes with no Co atoms, and ...
Tópico(s): Boron and Carbon Nanomaterials Research
2011 - American Physical Society | Physical Review B
Renee D. Diehl, Nicola Ferralis, K. Pussi, Milton W. Cole, Wahyu Setyawan, Stefano Curtarolo,
The ordering of physically adsorbed gases on quasicrystalline surfaces exemplifies the effects of competing interactions. In this study, grand canonical Monte Carlo simulations were performed to complement experimental measurements of the ordering of Xe adsorbed on the tenfold surface of decagonal Al–Ni–Co. The simulations employed a semi-empirical gas-surface interaction, based on conventional combining rules, and the Lennard–Jones Xe–Xe interaction. The simulation results are consistent with the ...
Tópico(s): nanoparticles nucleation surface interactions
2006 - Taylor & Francis | The Philosophical Magazine A Journal of Theoretical Experimental and Applied Physics
K. Pussi, Nicola Ferralis, M. Mihalkovič, Michael Widom, Stefano Curtarolo, M. Gierer, C. J. Jenks, P. C. Canfield, I. R. Fisher, Renee D. Diehl,
The determination of quasicrystal (QC) surface structures is a challenge to current surface structure techniques. Low-energy electron diffraction (LEED) is the primary technique for the determination of periodic surface structures, but application of dynamical LEED to quasicrystals requires the use of many approximations. In this study, two different approaches were used to apply dynamical LEED to the structure of the tenfold surface of decagonal ${\mathrm{Al}}_{73}{\mathrm{Ni}}_{10}{\mathrm{Co}}_{17}$. ...
Tópico(s): Microstructure and mechanical properties
2006 - American Physical Society | Physical Review B
K. Pussi, H. I. Li, Heekeun Shin, L. N. Serkovic Loli, A. K. Shukla, J. Ledieu, V. Fournée, L. L. Wang, S. Su, Kristin Marino, M Snyder, Renee D. Diehl,
We have used scanning tunneling microscopy (STM), low-energy electron diffraction (LEED), and density functional theory (DFT) to elucidate the structure and thermodynamics of the (2$\sqrt{3}$ \ifmmode\times\else\texttimes\fi{} 2$\sqrt{3}$)$R$30\ifmmode^\circ\else\textdegree\fi{} phase of C${}_{60}$ on Ag(111), which consists of a mixture of molecules in two different site/orientation states. The structure analysis identifies the two types of molecules as (1) sitting on a vacancy with a hexagon face down ...
Tópico(s): Graphene research and applications
2012 - American Physical Society | Physical Review B
Jouko Lahtinen, P. Kantola, S. Jaatinen, Karin Habermehl-Cwirzen, Petri Salo, Johannes Vuorinen, M. Lindroos, K. Pussi, Ari P. Seitsonen,
The geometric surface structure of a (2 × 2)-S layer formed by adsorption of hydrogen sulfide at 185 K on the Co(0 0 0 1) surface has been determined by low energy electron diffraction (LEED) experiments and density-functional theory (DFT) calculations. The favored atomic configuration consists of sulfur atoms residing at the fcc-hollow sites with S–Co distance of 2.2 ± 0.1 Å. Buckling in the first layer is negligible and the three nearest-neighbor Co atoms below the S atom are symmetrically moved by 0. ...
Tópico(s): Ammonia Synthesis and Nitrogen Reduction
2005 - Elsevier BV | Surface Science
Nicola Ferralis, Renee D. Diehl, K. Pussi, M. Lindroos, I. R. Fisher, C. J. Jenks,
The adsorption of Xe onto the tenfold surface of decagonal Al-Ni-Co was studied using low-energy electron diffraction (LEED). LEED isobar measurements indicate that Xe grows in a layer-by-layer mode for at least the first two layers in the temperature range 60--80 K. The half-monolayer isosteric heat of adsorption was measured to be $250\ifmmode\pm\else\textpm\fi{}10\mathrm{meV}.$ No superlattice was observed for the first layer of Xe, which is therefore presumed either to have a quasicrystalline ...
Tópico(s): nanoparticles nucleation surface interactions
2004 - American Physical Society | Physical Review B
Renee D. Diehl, Thomas Seyller, Mellita Caragiu, G. Leatherman, Nicola Ferralis, K. Pussi, P. Kaukasoina, M. Lindroos,
During the past six years, the adsorption geometries of several rare gases in structures having several different symmetries on a variety of substrates were determined using low-energy electron diffraction (LEED). In most of these studies, a preference is found for the rare gas atoms to adsorb in the low-coordination sites. Only in the case of adsorption on graphite has a clear preference for a high-coordination site for a rare gas atom been found. This unexpected behaviour is not yet completely ...
Tópico(s): Quantum, superfluid, helium dynamics
2004 - IOP Publishing | Journal of Physics Condensed Matter
Nicola Ferralis, K. Pussi, Erik J. Cox, M. Gierer, J. Ledieu, I. R. Fisher, C. J. Jenks, M. Lindroos, R. McGrath, Renee D. Diehl,
The structure of the tenfold surface of decagonal Al-Ni-Co was studied using low-energy electron diffraction (LEED) and scanning tunneling microscopy (STM). The surface region is a relaxed truncated bulk structure, having the same composition as the bulk. The outermost layer spacing is contracted by 10% relative to the bulk interlayer spacing, while the next layer spacing is expanded by 5%. A small degree of intralayer rumpling was observed within each layer. There is a one-to-one correspondence between ...
Tópico(s): Mineralogy and Gemology Studies
2004 - American Physical Society | Physical Review B
Nicola Ferralis, K. Pussi, Sharon Finberg, J. A. Smerdon, M. Lindroos, R. McGrath, Renee D. Diehl,
Potassium adsorption on graphite has been a model system for the understanding of the interaction of alkali metals with surfaces. The geometries of the $(2\ifmmode\times\else\texttimes\fi{}2)$ structure of potassium on both single-crystal graphite (SCG) and highly oriented pyrolytic graphite (HOPG) were investigated for various preparation conditions for graphite temperatures between 55 and 140 K. In all cases, the geometry was found to consist of $\mathrm{K}$ atoms in the hollow sites on top of the surface. ...
Tópico(s): Advancements in Battery Materials
2004 - American Physical Society | Physical Review B
Heekeun Shin, A. Schwarze, Renee D. Diehl, K. Pussi, A. Colombier, Émilie Gaudry, J. Ledieu, G. M. McGuirk, L. N. Serkovic Loli, V. Fournée, L. L. Wang, Guillaume Schull, Richard Berndt,
Earlier studies of ${\text{C}}_{60}$ adsorption on Au(111) reported many interesting and complex features. We have performed coordinated low-energy electron diffraction, scanning tunneling microscopy (STM), and density functional theory studies to elucidate some of the details of the monolayer commensurate (2\ensuremath{\surd}3 \ifmmode\times\else\texttimes\fi{} 2\ensuremath{\surd}3)R30\ifmmode^\circ\else\textdegree\fi{} phase. We have identified the adsorption geometries of the two states that image ...
Tópico(s): Diamond and Carbon-based Materials Research
2014 - American Physical Society | Physical Review B
Sampsa K. Hämäläinen, Mark P. Boneschanscher, Peter H. Jacobse, Ingmar Swart, K. Pussi, W. Moritz, Jouko Lahtinen, Peter Liljeroth, Jani Sainio,
We have studied the incommensurate moir\'e structure of epitaxial graphene grown on iridium(111) by dynamic low-energy electron diffraction [LEED $I$($V$)] and noncontact atomic force microscopy (AFM) with a CO-terminated tip. Our LEED $I$($V$) results yield the average positions of all the atoms in the surface unit cell and are in qualitative agreement with the structure obtained from density functional theory. The AFM experiments reveal local variations of the moir\'e structure: The corrugation varies ...
Tópico(s): Molecular Junctions and Nanostructures
2013 - American Physical Society | Physical Review B
A. Matilainen, K. Pussi, Renee D. Diehl, M. Hahne, P. Gille, Émilie Gaudry, L. N. Serkovic Loli, G. M. McGuirk, M.-C. de Weerd, V. Fournée, J. Ledieu,
Complex metallic alloys having isolated transition-metal elements in the surface layer have been reported to work well as selective hydrogenation catalysts. We report an experimental determination of the surface structure of one such compound $\mathrm{A}{\mathrm{l}}_{13}\mathrm{F}{\mathrm{e}}_{4}(010)$. The structure was determined using low-energy electron diffraction. The best-fit structure terminates in a layer similar to the puckered bulk layer but lacking some of the Al and Fe atoms. Protruding ...
Tópico(s): Advanced Chemical Physics Studies
2015 - American Physical Society | Physical Review B
Lindsay R. Merte, Mathias Jørgensen, K. Pussi, Johan Gustafson, Mikhail Shipilin, Andreas Schaefer, Chu Zhang, Jonathan Rawle, Chris Nicklin, G. Thornton, R. Lindsay, Bjørk Hammer, Edvin Lundgren,
Using surface x-ray diffraction (SXRD), quantitative low-energy electron diffraction (LEED), and density-functional theory (DFT) calculations, we have determined the structure of the ($4\ifmmode\times\else\texttimes\fi{}1$) reconstruction formed by sputtering and annealing of the ${\mathrm{SnO}}_{2}(110)$ surface. We find that the reconstruction consists of an ordered arrangement of ${\mathrm{Sn}}_{3}{\mathrm{O}}_{3}$ clusters bound atop the bulk-terminated ${\mathrm{SnO}}_{2}(110)$ surface. The model was found ...
Tópico(s): ZnO doping and properties
2017 - American Physical Society | Physical Review Letters
Daniel W. Davies, Aron Walsh, James J. Mudd, C. F. McConville, Anna Regoutz, Juhan Matthias Kahk, David J. Payne, V.R. Dhanak, David Hesp, K. Pussi, Tien-Lin Lee, R.G. Egdell, Kelvin H. L. Zhang,
Indium oxide is widely used as a transparent electrode in optoelectronic devices and as a photocatalyst with activity for reduction of CO2. However, very little is known about the structural and electronic properties of its surfaces, particularly those prepared under reducing conditions. In this report, directional "lone-pair" surface states associated with filled 5s2 orbitals have been identified on vacuum-annealed In2O3(111) through a combination of hard and soft X-ray photoemission spectroscopy ...
Tópico(s): ZnO doping and properties
2018 - American Chemical Society | The Journal of Physical Chemistry C
Johannes Nokelainen, Christopher Lane, R. S. Markiewicz, B. Barbiellini, Aki Pulkkinen, Bahadur Singh, Jianwei Sun, K. Pussi, Arun Bansil,
Bi-based cuprate superconductors are important materials for both fundamental research and applications. As in other cuprates, the superconducting phase in the Bi compounds lies close to an antiferromagnetic phase. Our density functional theory calculations based on the strongly-constrained-and-appropriately-normed exchange correlation functional in ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2}{\mathrm{CaCu}}_{2}{\mathrm{O}}_{8+\ensuremath{\delta}}$ reveal the persistence of magnetic moments on the copper ions ...
Tópico(s): Advanced Condensed Matter Physics
2020 - American Physical Society | Physical review. B./Physical review. B
Aki Pulkkinen, B. Barbiellini, Johannes Nokelainen, V. V. Sokolovskiy, Д. Р. Байгутлин, О. Н. Мирошкина, М. А. Загребин, V. D. Buchelnikov, Christopher Lane, R. S. Markiewicz, Arun Bansil, Jianwei Sun, K. Pussi, E. Lähderanta,
We have investigated the interplay between magnetic and structural degrees of freedom in elemental Mn. The equilibrium volume is shown to depend critically on the magnetic interactions between the Mn atoms. While the standard generalized-gradient-approximation underestimates the equilibrium volume, a more accurate treatment of the effects of electronic localization and magnetism is found to solve this longstanding problem. We capture well the complexity of the large 58 atoms per unit cell $α$-Mn ...
Tópico(s): Heusler alloys: electronic and magnetic properties
2020 - American Physical Society | Physical review. B./Physical review. B
Marc Walker, M. G. Brown, M. Draxler, M. G. Dowsett, C. F. McConville, T.C.Q. Noakes, Paul Bailey,
... optimization of the surface alloy model proposed by Pussi [K. Pussi et al., Surf. Sci. 549 (2004) 24]. Different ...
Tópico(s): Metal and Thin Film Mechanics
2011 - Elsevier BV | Surface Science
K. Pussi, M. Lindroos, J. Katainen, Karin Habermehl-Cwirzen, Jouko Lahtinen, Ari P. Seitsonen,
The geometric structure of a Co{0001}-(7×7)R19.1°–C6H6 surface formed by adsorption of benzene to the saturation coverage at 170 K has been determined by low energy electron diffraction (LEED). The favored model consists of a flat laying, nearly undisturbed benzene molecule, with the hydrogen–carbon bonds bent away from the substrate by 0.3 ± 0.2 Å. The carbon ring lies at a hcp-site with the two parallel C–C bonds aligned with [11¯00] direction. Buckling between the inequivalent carbon atoms in the ...
Tópico(s): Chemical and Physical Properties of Materials
2004 - Elsevier BV | Surface Science
Д. Р. Байгутлин, V. V. Sokolovskiy, О. Н. Мирошкина, М. А. Загребин, Johannes Nokelainen, Aki Pulkkinen, B. Barbiellini, K. Pussi, E. Lähderanta, V. D. Buchelnikov, A. T. Zayak,
The stability of the nonmodulated martensitic phase, the austenitic Fermi surface, and the phonon dispersion relations for ferromagnetic ${\mathrm{Ni}}_{2}\mathrm{MnGa}$ are studied using density functional theory. Exchange-correlation effects are considered with various degrees of precision, starting from the simplest local spin density approximation (LSDA), then adding corrections within the generalized gradient approximation (GGA), and finally, including the meta-GGA corrections within the strongly ...
Tópico(s): Magnetic Properties of Alloys
2020 - American Physical Society | Physical review. B./Physical review. B
I.M. McLeod, V.R. Dhanak, A. Matilainen, M. Lahti, K. Pussi, K.H.L. Zhang,
The deposition of 1/3 of a monolayer of Bi on Ag(111) leads to the formation of BiAg2 surface alloy with a long range ordered 3×3R30∘ superstructure. A detailed analysis of this structure using LEED I–V measurements together with DFT calculations is presented. We find strong correlation between experimental and calculated LEED I–V data, with the fit between the two data sets having a Pendry's reliability factor of 0.16. The Bi atom is found to replace one top layer Ag atom in each unit cell, forming ...
Tópico(s): Superconductivity in MgB2 and Alloys
2010 - Elsevier BV | Surface Science