| 51. |
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| 52. |
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| 53. |
- Zarechnaya, E. Y., et al.
(författare)
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Theoretical study of linear monoatomic nanowires, dimer and bulk of Cu, Ag, Au, Ni, Pd and Pt
- 2008
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Ingår i: Computational materials science. - : Elsevier BV. - 0927-0256 .- 1879-0801. ; 43:3, s. 522-530
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Tidskriftsartikel (refereegranskat)abstract
- The binding and electronic properties of monoatomic nanowires, dimers and bulk structures of Cu, Ag, Au and Ni, Pd, Pt have been studied by the projector augmented-wave method (PAW) within the density functional theory (DFT) using the local density approximation (LDA) as well as generalized gradient approximation (GGA) in both Perdew-Wang (PW91) and Perdew-Burke-Ernzerhof (PBE) parameterizations. Our results show that the formation of atomic chains is not equally plausible for all the studied elements. In agreement with experimental observations Pt and An stand out as most likely elements to form monoatomic wires. Changes in the electronic structure and magnetic properties of metal chains at stretching are analyzed.
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| 54. |
- Vitos, Levente, et al.
(författare)
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Stacking fault energy and magnetism in austenitic stainless steels
- 2008
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Ingår i: Physica Scripta. - : Institute of Physics (IOP). - 0031-8949 .- 1402-4896. ; 77:6
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Tidskriftsartikel (refereegranskat)abstract
- The stacking fault energies are used to illustrate the footprint of magnetism on the mechanical properties of Fe-Cr-Ni alloys forming the basis of austenitic stainless steels. We find that the usual chemical effects of alloying additions are accompanied by major magnetic effects, which stabilize the most common industrial alloy steels at normal service temperatures. We suggest that part of the uncertainties associated with the experimental data on the stacking fault energies are due to the strong concentration and temperature dependence originating from the persisting local magnetic moments.
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| 55. |
- Lang, J. J. K., et al.
(författare)
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Tin-stabilized (1 x 2) and (1 x 4) reconstructions on GaAs(100) and InAs(100) studied by scanning tunneling microscopy, photoelectron spectroscopy, and ab initio calculations
- 2011
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Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 605:9-10, s. 883-888
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Tidskriftsartikel (refereegranskat)abstract
- Tin (Sn) induced (1 x 2) reconstructions on GaAs(100) and InAs(100) substrates have been studied by low energy electron diffraction (LEED), photoelectron spectroscopy, scanning tunneling microscopy/spectroscopy (STM/STS) and ab initio calculations. The comparison of measured and calculated STM images and surface core-level shifts shows that these surfaces can be well described with the energetically stable building blocks that consist of Sn-III dimers. Furthermore, a new Sn-induced (1 x 4) reconstruction was found. In this reconstruction the occupied dangling bonds are closer to each other than in the more symmetric (1 x 2) reconstruction, and it is shown that the (1 x 4) reconstruction is stabilized as the adatom size increases.
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| 56. |
- Vitos, Levente, et al.
(författare)
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Alloying effects on the stacking fault energy in austenitic stainless steels from first-principles theory
- 2006
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Ingår i: Acta Materialia. - : Elsevier BV. - 1359-6454 .- 1873-2453. ; 54:14, s. 3821-3826
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Tidskriftsartikel (refereegranskat)abstract
- The stacking fault energy (SFE) of austenitic stainless steels has been determined using a quantum mechanical first-principles approach. We identify the electronic, magnetic and volume effects responsible for the compositional dependence of the SFE. We find that both the alloying element and the composition of the host material are important for understanding the alloying effects. Our results show that no simple and universally valid composition equations exist for the SEE.
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| 57. |
- Johansson, Börje M., et al.
(författare)
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Internal and external knowledge and introduction of export varieties
- 2015
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Ingår i: The World Economy. - : Wiley. - 0378-5920 .- 1467-9701. ; 38:4, s. 629-654
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Tidskriftsartikel (refereegranskat)abstract
- Firms in local industries maintain their capability to generate new export varieties by simultaneously exploiting internal and external knowledge resources. The paper introduces the notion 'variety triplet' to distinguish individual export varieties, where a triplet is a unique combination of a firm, a product code and a destination country. For each date, the set of variety triplets in each local industry records all remaining export varieties introduced in the past. In view of this, the paper examines how internal and external knowledge of local industries influence the industry's scope and value of export varieties. First, the paper contributes by considering a local industry's internal and external knowledge, as well as the conjunction of its internal and external knowledge sources. Second, the knowledge sources are shown to influence both the stock and the dynamics of a local industry's variety triplets, using firm-level data from Sweden.
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| 58. |
- Kuzmin, M., et al.
(författare)
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Atomic structure of Yb/Si(100)(2X6) : Interrelation between the silicon dimer arrangement and Si 2p photoemission line shape
- 2010
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 82:11, s. 113302-
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Tidskriftsartikel (refereegranskat)abstract
- Combining photoelectron spectroscopy and density-functional theory calculations, we have studied the atomic geometry of Yb/Si(100)(2 X 6) reconstruction and the mechanisms responsible for its stabilization as well as the influence of this reconstruction on Si 2p core-level photoemission. The analysis of measured and calculated surface core-level shifts supports the recently proposed model of the Yb/Si(100)(2 X 6). It involves, in agreement with valence-band measurements, unbuckled (symmetrical) silicon dimers, leading to unusually narrowed Si 2p line shape as compared to those of related systems. The origin of the symmetrical dimers in the (2 X 6) structure is discussed in the context of previous results in literature.
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| 59. |
- Kuzmin, M., et al.
(författare)
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Surface core-level shifts on Ge(111)c(2 x 8) : Experiment and theory
- 2011
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 83:24, s. 245319-
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Tidskriftsartikel (refereegranskat)abstract
- Combining high-resolution photoelectron spectroscopy and density functional theory (DFT) calculations, 3d photoemission line shape and surface core-level shifts have been reinvestigated on the Ge(111)c(2 x 8) surface. It is found that 3d spectra include, in addition to the bulk and three surface-shifted components reported in literature, a component that was not identified in earlier measurements with a lower resolution. The detailed interpretation of these spectra and their line shape is made on the basis of DFT calculations. It is shown that the lowest binding energy component is due to the rest atoms. The higher binding energy emission is caused by the adatoms and the third-layer atoms that are below the adatoms. Finally, the two other surface components originate from the first- and second-layer atoms. The screening effects in the Ge(111)c(2 x 8) are discussed.
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| 60. |
- Laukkanen, P., et al.
(författare)
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Formation and destabilization of Ga interstitials in GaAsN : Experiment and theory
- 2012
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 86:19, s. 195205-
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Tidskriftsartikel (refereegranskat)abstract
- Using first-principles total energy calculations we have found complex defects induced by N incorporation in GaAsN. The formation energy of the Ga interstitial atom is very significantly decreased due to local effects within the defect complex. The stability of the Ga interstitials is further increased at surfaces. The present results suggest that the energetically favorable Ga interstitial atoms are much more abundant in GaAsN than the previously considered N defects, which have relatively large formation energies. Our synchrotron radiation core-level photoemission measurements support the computational results. The formation of harmful Ga interstitials should be reduced by incorporating large group IV B atoms in GaAsN.
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