uu.seUppsala University Publications
Change search
Link to record
Permanent link

Direct link
BETA
Johansson, Börje
Alternative names
Publications (10 of 274) Show all publications
Tao, Q., Lu, J., Dahlqvist, M., Mockute, A., Calder, S., Petruhins, A., . . . Rosen, J. (2019). Atomically Layered and Ordered Rare-Earth i-MAX Phases: A New Class of Magnetic Quaternary Compounds. Chemistry of Materials, 31(7), 2476-2485
Open this publication in new window or tab >>Atomically Layered and Ordered Rare-Earth i-MAX Phases: A New Class of Magnetic Quaternary Compounds
Show others...
2019 (English)In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 31, no 7, p. 2476-2485Article in journal (Refereed) Published
Abstract [en]

In 2017, we discovered quaternary i-MAX phases atomically layered solids, where M is an early transition metal, A is an A group element, and X is C—with a (M12/3M21/3)2AC chemistry, where the M1 and M2 atoms are in-plane ordered. Herein, we report the discovery of a class of magnetic i-MAX phases in which bilayers of a quasi-2D magnetic frustrated triangular lattice overlay a Mo honeycomb arrangement and an Al Kagome lattice. The chemistry of this family is (Mo2/3RE1/3)2AlC, and the rare-earth, RE, elements are Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, and Lu. The magnetic properties were characterized and found to display a plethora of ground states, resulting from an interplay of competing magnetic interactions in the presence of magnetocrystalline anisotropy.

National Category
Condensed Matter Physics Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-382860 (URN)10.1021/acs.chemmater.8b05298 (DOI)000464477100029 ()
Funder
Knut and Alice Wallenberg Foundation, KAW 2015.0043Swedish Research Council, 642-2013-8020Swedish Research Council, 2015-00607Swedish Research Council, 621-2014-4890Swedish National Infrastructure for Computing (SNIC)German Research Foundation (DFG), SA 3095/2-1
Available from: 2019-05-10 Created: 2019-05-10 Last updated: 2019-05-10Bibliographically approved
Al-Zoubi, N., Schonecker, S., Li, X., Li, W., Johansson, B. & Vitos, L. (2019). Elastic properties of 4d transition metal alloys: Values and trends. Computational materials science, 159, 273-280
Open this publication in new window or tab >>Elastic properties of 4d transition metal alloys: Values and trends
Show others...
2019 (English)In: Computational materials science, ISSN 0927-0256, E-ISSN 1879-0801, Vol. 159, p. 273-280Article in journal (Refereed) Published
Abstract [en]

Using the Exact Muffin-Tin Orbitals method within the Perdew-Burke-Ernzerhof exchange-correlation approximation for solids and solid surfaces (PBEso1), we study the single crystal elastic constants of 4d transition metals (atomic number Z between 39 and 47) and their binary alloys in the body centered cubic (bcc) and face centered cubic (fcc) structures. Alloys between the first neighbors Z(Z + 1) and between the second neighbors Z(Z + 2) are considered. The lattice constants, bulk moduli and elastic constants are found in good agreement with the available experimental and theoretical data. It is shown that the correlation between the relative tetragonal shear elastic constant C-fcc'-2C(bcc)' and the structural energy difference between the fcc and bcc lattices Delta E is superior to the previously considered models. For a given crystal structure, the equiatomic Z(Z + 2) alloys turn out to have similar structural and elastic properties as the pure elements with atomic number (Z + 1). Furthermore, alloys with composition Z(1-x)(Z + 2)(x) possess similar properties as Z(1-2x)(Z + 1)(2x). The present theoretical data on the structural and the elastic properties of 4d transition metal alloys provides consistent input for coarse scale modeling of material properties.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2019
Keywords
Exact muffin-tin orbital method, 4d transition metals, Binary alloys, Elastic constants, First-principles, Structural properties
National Category
Condensed Matter Physics Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:uu:diva-378523 (URN)10.1016/j.commatsci.2018.12.027 (DOI)000457856900027 ()
Funder
Swedish Research CouncilSwedish Foundation for Strategic Research The Swedish Foundation for International Cooperation in Research and Higher Education (STINT)Carl Tryggers foundation
Available from: 2019-03-25 Created: 2019-03-25 Last updated: 2019-03-25Bibliographically approved
Li, X., Schonecker, S., Li, X., Hao, S., Zhao, J., Johansson, B. & Vitos, L. (2019). First-principles study of crystal-face specificity in surface properties of Fe-rich Fe-Cr alloys. PHYSICAL REVIEW MATERIALS, 3(3), Article ID 034401.
Open this publication in new window or tab >>First-principles study of crystal-face specificity in surface properties of Fe-rich Fe-Cr alloys
Show others...
2019 (English)In: PHYSICAL REVIEW MATERIALS, ISSN 2475-9953, Vol. 3, no 3, article id 034401Article in journal (Refereed) Published
Abstract [en]

A density-functional theory investigation of the (100) and (110) surfaces of the body-centered cubic (bcc) Fe1-xbCrxb binary alloys, x(b) <= 15 at.%, is reported. The energies and segregation energies of these surfaces were calculated for chemically homogeneous concentration profiles and for Cr surface contents deviating from the nominal one of the bulk. The implications of these results for the surface alloy phase diagram are discussed. The surface chemistry of Fe-Cr(100) is characterized by a transition from Cr depletion to Cr enrichment in a critical bulk Cr composition window of 6 < x(b) < 9 at.%. In contrast, such threshold behavior of the surface Cr content is absent for Fe-Cr(110) and a nearly homogeneous Cr concentration profile is energetically favorable. The strongly suppressed surface-layer relaxation at both surfaces is shown to be of magnetic origin. The compressive, magnetic contribution to the surface relaxation stress is found to correlate well with the surface magnetic moment squared at both surface terminations. The stability of the Cr surface magnetic moments against bulk Cr content is clarified based on the surface electronic structure.

National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-379928 (URN)10.1103/PhysRevMaterials.3.034401 (DOI)000460683400001 ()
Funder
Swedish Research CouncilSwedish Foundation for Strategic Research
Available from: 2019-03-28 Created: 2019-03-28 Last updated: 2019-03-28Bibliographically approved
Diklic, N. P., Dobrota, A. S., Pasti, I. A., Mentus, S. V., Johansson, B. & Skorodumova, N. V. (2019). Sodium storage via single epoxy group on graphene: The role of surface doping. Electrochimica Acta, 297, 523-528
Open this publication in new window or tab >>Sodium storage via single epoxy group on graphene: The role of surface doping
Show others...
2019 (English)In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 297, p. 523-528Article in journal (Refereed) Published
Abstract [en]

Due to its unique physical and chemical properties, graphene is being considered as a promising material for energy conversion and storage applications. Introduction of functional groups and dopants on/in graphene is a useful strategy for tuning its properties. In order to fully exploit its potential, atomic-level understanding of its interaction with species of importance for such applications is required. We present a DFT study of the interaction of sodium atoms with epoxy-graphene and analyze how this interaction is affected upon doping with boron and nitrogen. We demonstrate how the dopants, combined with oxygen-containing groups alter the reactivity of graphene towards Na. Dopants act as attractors of epoxy groups, enhancing the sodium adsorption on doped oxygen-functionalized graphene when compared to the case of non-doped epoxy-graphene. Furthermore, by considering thermodynamics of the Na interaction with doped epoxy-graphene it has been concluded that such materials are good candidates for Na storage applications. Therefore, we suggest that controlled oxidation of doped carbon materials could lead to the development of advanced anode materials for rechargeable Na-ion batteries.

Keywords
Graphene, Graphene doping, Graphene oxidation, Sodium storage, Battery
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-375795 (URN)10.1016/j.electacta.2018.11.108 (DOI)000455642500058 ()
Funder
Swedish Research Council, 2014-5993Carl Tryggers foundation , 17:503Swedish National Infrastructure for Computing (SNIC)
Available from: 2019-02-15 Created: 2019-02-15 Last updated: 2019-02-15Bibliographically approved
Pasti, I. A., Jovanovic, A., Dobrota, A. S., Mentus, S. V., Johansson, B. & Skorodumova, N. V. (2018). Atomic adsorption on graphene with a single vacancy: systematic DFT study through the periodic table of elements. Physical Chemistry, Chemical Physics - PCCP, 20(2), 858-865
Open this publication in new window or tab >>Atomic adsorption on graphene with a single vacancy: systematic DFT study through the periodic table of elements
Show others...
2018 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 20, no 2, p. 858-865Article in journal (Refereed) Published
Abstract [en]

Vacancies in graphene present sites of altered chemical reactivity and open possibilities to tune graphene properties by defect engineering. The understanding of chemical reactivity of such defects is essential for successful implementation of carbon materials in advanced technologies. We report the results of a systematic DFT study of atomic adsorption on graphene with a single vacancy for the elements of rows 1-6 of the periodic table of elements (PTE), excluding lanthanides. The calculations have been performed using the PBE, long-range dispersion interaction-corrected PBE (PBE+D2 and PBE+D3) and non-local vdW-DF2 functionals. We find that most elements strongly bind to the vacancy, except for the elements of groups 11 and 12, and noble gases, for which the contribution of dispersion interaction to bonding is most significant. The strength of the interaction with the vacancy correlates with the cohesive energy of the elements in their stable phases: the higher the cohesive energy is, the stronger bonding to the vacancy can be expected. As most atoms can be trapped at the SV site we have calculated the potentials of dissolution and found that in most cases the metals adsorbed at the vacancy are more "noble" than they are in their corresponding stable phases.

National Category
Chemical Sciences Physical Sciences
Identifiers
urn:nbn:se:uu:diva-341487 (URN)10.1039/c7cp07542a (DOI)000419219700015 ()29238768 (PubMedID)
Available from: 2018-02-28 Created: 2018-02-28 Last updated: 2018-02-28Bibliographically approved
Pasti, I. A., Jovanovic, A., Dobrota, A. S., Mentus, S. V., Johansson, B. & Skorodumova, N. V. (2018). Atomic adsorption on pristine graphene along the Periodic Table of Elements - From PBE to non-local functionals. Applied Surface Science, 436, 433-440
Open this publication in new window or tab >>Atomic adsorption on pristine graphene along the Periodic Table of Elements - From PBE to non-local functionals
Show others...
2018 (English)In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 436, p. 433-440Article in journal (Refereed) Published
Abstract [en]

The understanding of atomic adsorption on graphene is of high importance for many advanced technologies. Here we present a complete database of the atomic adsorption energies for the elements of the Periodic Table up to the atomic number 86 (excluding lanthanides) on pristine graphene. The energies have been calculated using the projector augmented wave (PAW) method with PBE, long-range dispersion interaction corrected PBE (PBE+D2, PBE+D3) as well as non-local vdW-DF2 approach. The inclusion of dispersion interactions leads to an exothermic adsorption for all the investigated elements. Dispersion interactions are found to be of particular importance for the adsorption of low atomic weight earth alkaline metals, coinage and s-metals (11th and 12th groups), high atomic weight p-elements and noble gases. We discuss the observed adsorption trends along the groups and rows of the Periodic Table as well some computational aspects of modelling atomic adsorption on graphene.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2018
Keywords
Graphene, Adsorption, Atomic adsorption, Periodic Table of Elements, Dispersion interactions
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-350485 (URN)10.1016/j.apsusc.2017.12.046 (DOI)000425723100050 ()
Funder
Swedish Research Council, 348-2012-6196]Swedish Research Council, 2014-5993]Carl Tryggers foundation
Available from: 2018-05-17 Created: 2018-05-17 Last updated: 2018-05-17Bibliographically approved
Jovanovic, A., Dobrota, A. S., Rafailovic, L. D., Mentus, S. V., Pasti, I. A., Johansson, B. & Skorodumova, N. V. (2018). Structural and electronic properties of V2O5 and their tuning by doping with 3d elements - modelling using the DFT plus U method and dispersion correction. Physical Chemistry, Chemical Physics - PCCP, 20(20), 13934-13943
Open this publication in new window or tab >>Structural and electronic properties of V2O5 and their tuning by doping with 3d elements - modelling using the DFT plus U method and dispersion correction
Show others...
2018 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 20, no 20, p. 13934-13943Article in journal (Refereed) Published
Abstract [en]

New electrode materials for alkaline-ion batteries are a timely topic. Among many promising candidates, V2O5 is one of the most interesting cathode materials. While having very high theoretical capacity, in practice, its performance is hindered by its low stability and poor conductivity. As regards the theoretical descriptions of V2O5, common DFT-GGA calculations fail to reproduce both the electronic and crystal structures. While the band gap is underestimated, the interlayer spacing is overestimated as weak dispersion interactions are not properly described within GGA. Here we show that the combination of the DFT+U method and semi-empirical D2 correction can compensate for the drawbacks of the GGA when it comes to the modelling of V2O5. When compared to common PBE calculations, with a modest increase in the computational cost, PBE+U+D2 fully reproduced the experimental band gap of V2O5, while the errors in the lattice parameters are only a few percent. Using the proposed PBE+U+D2 methodology we studied the doping of V2O5 with 3d elements (from Sc to Zn). We show that both the structural and electronic parameters are affected by doping. Most importantly, a significant increase in conductivity is expected upon doping, which is of great importance for the application of V2O5 in metal-ion batteries.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2018
National Category
Theoretical Chemistry
Identifiers
urn:nbn:se:uu:diva-357738 (URN)10.1039/c8cp00992a (DOI)000433262300026 ()29744500 (PubMedID)
Funder
Swedish Research Council, 2014-5993
Available from: 2018-08-30 Created: 2018-08-30 Last updated: 2018-08-30Bibliographically approved
Lee, J.-Y. -., Punkkinen, M. P., Schönecker, S., Nabi, Z., Kádas, K., Zolyomi, V., . . . Kwon, S. K. (2018). The surface energy and stress of metals. Surface Science, 674, 51-68
Open this publication in new window or tab >>The surface energy and stress of metals
Show others...
2018 (English)In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 674, p. 51-68Article in journal (Refereed) Published
Abstract [en]

We investigated surface properties of metals by performing first-principles calculations. A systematic database was established for the surface relaxation, surface energy (gamma), and surface stress (tau) 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 gamma of simple metals decreases as the atomic number increases in a given group, while the surface stress tau has its minimum in the middle. The transition metal series show parabolic trends for both gamma and tau 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 gamma and tau 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 tau for the (100) surface facet, indicating that they are under compression. The light actinides have an increasing gamma trend according to the atomic number. The present work provides a useful and consistent database for the theoretical modelling of surface phenomena.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2018
Keywords
Surface relaxation, Surface energy, Surface stress, Density-functional theory calculations, Metals
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-356604 (URN)10.1016/j.susc.2018.03.008 (DOI)000432759200009 ()
Funder
Swedish Research CouncilSwedish Foundation for Strategic Research VINNOVA, 2014-03374Swedish Energy AgencyThe Swedish Foundation for International Cooperation in Research and Higher Education (STINT)Carl Tryggers foundation
Available from: 2018-08-03 Created: 2018-08-03 Last updated: 2018-08-03Bibliographically approved
Pasti, I. A., Johansson, B. & Skorodumova, N. V. (2018). Tunable reactivity of supported single metal atoms by impurity engineering of the MgO(001) support. Physical Chemistry, Chemical Physics - PCCP, 20(9), 6337-6346
Open this publication in new window or tab >>Tunable reactivity of supported single metal atoms by impurity engineering of the MgO(001) support
2018 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 20, no 9, p. 6337-6346Article in journal (Refereed) Published
Abstract [en]

Development of novel materials may often require a rational use of high price components, like noble metals, in combination with the possibility to tune their properties in a desirable way. Here we present a theoretical DFT study of Au and Pd single atoms supported by doped MgO(001). By introducing B, C and N impurities into the MgO(001) surface, the interaction between the surface and the supported metal adatoms can be adjusted. Impurity atoms act as strong binding sites for Au and Pd adatoms and can help to produce highly dispersed metal particles. The reactivity of metal atoms supported by doped MgO(001), as probed by CO, is altered compared to their counterparts on pristine MgO(001). We find that Pd atoms on doped MgO(001) are less reactive than on perfect MgO(001). In contrast, Au adatoms bind CO much more strongly when placed on doped MgO(001). In the case of Au on N-doped MgO(001) we find that charge redistribution between the metal atom and impurity takes place even when not in direct contact, which enhances the interaction of Au with CO. The presented results suggest possible ways for optimizing the reactivity of oxide supported metal catalysts through impurity engineering.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2018
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-352729 (URN)10.1039/c7cp08370j (DOI)000429280100034 ()29435542 (PubMedID)
Funder
Swedish Research Council, 2014-5993Carl Tryggers foundation
Available from: 2018-06-07 Created: 2018-06-07 Last updated: 2018-06-07Bibliographically approved
Jovanovic, A., Petkovic, M., Pasti, I. A., Johansson, B. & Skorodumova, N. V. (2018). Tuning the electronic and chemisorption properties of hexagonal MgO nanotubes by doping: Theoretical study. Applied Surface Science, 457, 1158-1166
Open this publication in new window or tab >>Tuning the electronic and chemisorption properties of hexagonal MgO nanotubes by doping: Theoretical study
Show others...
2018 (English)In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 457, p. 1158-1166Article in journal (Refereed) Published
Abstract [en]

Oxide materials offer a wide range of interesting physical and chemical properties. Even more versatile behavior of oxides is seen at the nanoscale, qualifying these materials for a number of applications. In this study we used DFT calculations to investigate the physical and chemical properties of small hexagonal MgO nanotubes of different length. We analyzed the effect of Li, B, C, N, and F doping on the properties of the nanotubes. We find that all dopants favor the edge positions when incorporated into the nanotubes. Doping results in the net magnetization whose value depends on the type of the impurity. Using the CO molecule as a probe, we studied the adsorption properties of pristine and doped MgO nanotubes. Our results show that the dopant sites are also the centers of significantly altered chemical reactivity. While pristine MgO nanotubes adsorb CO weakly, very strong adsorption at the dopant sites (B-, C-, and N-doped nanotubes) or neighboring edge atoms (F- and Li-doped nanotubes) is observed. Our results suggest that impurity engineering in oxide materials can be a promising strategy for the development of novel materials with possible use as selective adsorbents or catalysts.

Keywords
Magnesium oxide, Nanotube, Doping, Surface reactivity
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-364122 (URN)10.1016/j.apsusc.2018.07.041 (DOI)000441872300136 ()
Funder
Swedish Research CouncilCarl Tryggers foundation
Available from: 2018-10-24 Created: 2018-10-24 Last updated: 2018-10-24Bibliographically approved
Organisations

Search in DiVA

Show all publications