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- Lee, J. -Y, et al.
(författare)
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The surface energy and stress of metals
- 2018
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Ingår i: Surface Science. - : Elsevier. - 0039-6028 .- 1879-2758. ; 674, s. 51-68
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Tidskriftsartikel (refereegranskat)abstract
- We investigated surface properties of metals by performing first-principles calculations. A systematic database was established for the surface relaxation, surface energy (γ), and surface stress (τ) for metallic elements in the periodic table. The surfaces were modeled by multi-layered slab structures along the direction of low-index surfaces. The surface energy γ of simple metals decreases as the atomic number increases in a given group, while the surface stress τ has its minimum in the middle. The transition metal series show parabolic trends for both γ and τ with a dip in the middle. The dip occurs at half-band filling due to a long-range Friedel oscillation of the surface charge density, which induces a strong stability to the Peierls-like transition. In addition, due to magnetic effects, the dips in the 3d metal series are shallower and deeper for γ and τ, respectively, than those of the 4d and 5d metals. The surface stress of the transition metals is typically positive, only Cr and Mn have a negative τ for the (100) surface facet, indicating that they are under compression. The light actinides have an increasing γ trend according to the atomic number. The present work provides a useful and consistent database for the theoretical modelling of surface phenomena.
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| 4. |
- Niklasson, Bo, et al.
(författare)
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Development of type 1 diabetes in wild bank voles associated with islet autoantibodies and the novel ljungan virus.
- 2003
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Ingår i: International journal of experimental diabesity research. - : Hindawi Limited. ; 4:1, s. 35-44
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Tidskriftsartikel (refereegranskat)abstract
- Wild bank voles (Clethrionomys glareolus) may develop diabetes in laboratory captivity. The aim of this study was to test whether bank voles develop type 1 diabetes in association with Ljungan virus. Two groups of bank voles were analyzed for diabetes, pancreas histology, autoantibodies to glutamic acid decarboxylase (GAD65), IA-2, and insulin by standardized radioligand-binding assays as well as antibodies to in vitro transcribed and translated Ljungan virus antigens. Group A represented 101 trapped bank voles, which were screened for diabetes when euthanized within 24 hours of capture. Group B represented 67 bank voles, which were trapped and kept in the laboratory for 1 month before being euthanized. Group A bank voles did not have diabetes. Bank voles in group B (22/67; 33%) developed diabetes due to specific lysis of pancreatic islet beta cells. Compared to nondiabetic group B bank voles, diabetic animals had increased levels of GAD65 (P < .0001), IA-2 (P < .0001), and insulin (P
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| 5. |
- Schönecker, Stephan, et al.
(författare)
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Surface parameters of ferritic iron-rich Fe-Cr alloy
- 2013
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Ingår i: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 25:30, s. 305002-
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Tidskriftsartikel (refereegranskat)abstract
- Using first-principles density functional theory in the implementation of the exact muffin-tin orbitals method and the coherent potential approximation, we studied the surface energy and the surface stress of the thermodynamically most stable surface facet (100) of the homogeneous disordered body-centred cubic iron-chromium system in the concentration interval up to 20 at.% Cr. For the low-index surface facets of Fe and Cr, the surface energy of Cr is slightly larger than that of Fe, while the surface stress of Cr is considerably smaller than that of Fe. We find that Cr addition to Fe generally increases the surface energy of the Fe-Cr alloy; however, an increase of the bulk amount of Cr also increases the surface stress. As a result of this unexpected trend, the (100) surface of Fe-Cr becomes more stable against reconstruction with increasing Cr concentration. We show that the observed trends are of magnetic origin. In addition to the homogeneous alloy case, we also investigated the impact of surface segregation on both surface parameters.
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| 6. |
- Wolter, A. U. B., et al.
(författare)
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Field-induced quantum criticality in the Kitaev system alpha-RuCl3
- 2017
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Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 96:4
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Tidskriftsartikel (refereegranskat)abstract
- alpha-magnetic excitations akin to Kitaev's honeycomb-lattice spin liquid. We have performed a detailed specific-heat investigation at temperatures down to 0.4 K in applied magnetic fields up to 9 T for fields parallel to the ab plane. We find a suppression of the zero-field antiferromagnetic order, together with an increase of the low-temperature specific heat, with increasing field up to mu H-0(c) approximate to 6.9 T. Above H-c, the magnetic contribution to the low-temperature specific heat is strongly suppressed, implying the opening of a spin-excitation gap. Our data point toward a field-induced quantum critical point at H-c; this is supported by universal scaling behavior near H-c. Remarkably, the data also reveal the existence of a small characteristic energy scale well below 1 meV, above which the excitation spectrum changes qualitatively. We relate the data to theoretical calculations based on a J(1)-K-1-Gamma(1)-J(3) honeycomb model.
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| 7. |
- Yang, Yaochun, et al.
(författare)
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Corrigendum to “First-principles study of the Σ3(112) grain boundary in Fe-rich Fe-Cr alloys” [Scripta Materialia 181 (2020) 140-143] (Scripta Materialia (2020) 140-143 (S1359646220301056), (10.1016/j.scriptamat.2020.02.029))
- 2021
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Ingår i: Scripta Materialia. - : Elsevier BV. - 1359-6462 .- 1872-8456. ; 191, s. 202-203
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Tidskriftsartikel (refereegranskat)abstract
- The authors regret that in producing Figs. 1 and 2, and Table S1 in our article an inadvertent error was made when calculating the bulk reference energy using an incorrect lattice setting. The bulk reference energy was recalculated using the correct lattice setting. Correction of the error results in a systematic shift in the grain boundary (GB) energies towards higher energies; see the corrected figures and table below. The change weakens the effect of Cr on the GB energy of chemically homogenous Fe1-xCrx alloys as shown in Fig. 1 (squares, red line), but doesn't influence the trends for chemically inhomogeneous Fe1-xCrx alloys as shown in Fig. 2 and Table S1. The correction has no effect on the analysis of the results and the conclusions presented in the original paper. The authors would like to apologise for any inconvenience caused.
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