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Marten, Tobias
Publications (10 of 15) Show all publications
Marten, T., Alling, B., Isaev, E., Lind, H., Tasnadi, F., Hultman, L. & Abrikosov, I. (2012). First-principles study of the SiNx/TiN(001) interface. Physical Review B. Condensed Matter and Materials Physics, 85(10), 104106
Open this publication in new window or tab >>First-principles study of the SiNx/TiN(001) interface
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2012 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 85, no 10, p. 104106-Article in journal (Refereed) Published
Abstract [en]

The structure of the SiNx tissue phase in superhard TiN/SiNx nanocomposites has been debated in the literature. We present a theoretical investigation of the possibility of crystalline and coherent ( 001) interfaces that satisfies the two necessary criteria, stability with respect to lattice vibrations as well as to variations in stoichiometry. It is found that one monolayer of Si tetrahedrally coordinated by N in a B3-like geometry embedded between B1-TiN( 001) surfaces is both dynamically stable and thermodynamically stable with respect to vacancy formation. However, with increasing layer thickness the B3-type structure becomes unstable with respect to Si vacancy formation. Instead we suggest that a tetragonal D0(22)-like order of Si vacancies can stabilize the interface. These structures are in line with the experimental findings of the crystalline tissue phase which has coherent interfaces with TiN.

Place, publisher, year, edition, pages
American Physical Society, 2012
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-76187 (URN)10.1103/PhysRevB.85.104106 (DOI)000301334700002 ()
Available from: 2012-03-31 Created: 2012-03-30 Last updated: 2017-12-07
Olovsson, W., Holmstroem, E., Marten, T., Abrikosov, I. & Niklasson, A. M. (2011). Interface core-level shifts as a probe of embedded thin-film quality. Physical Review B. Condensed Matter and Materials Physics, 84(8), 085431
Open this publication in new window or tab >>Interface core-level shifts as a probe of embedded thin-film quality
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2011 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 84, no 8, p. 085431-Article in journal (Refereed) Published
Abstract [en]

We use first-principles calculations of layer-resolved core-level binding energy shifts (CLSs) within density functional theory as away to characterize the interface quality and thickness in embedded thin-film nanomaterials. A closer study of interfaces is motivated as properties specific to nanostructures can be related directly to the interface environment or indirectly as interference effects due to quantum confinement. From an analysis based on the Cu 2p(3/2) CLS for Cu embedded in Ni and Co fcc (100) and Fe bcc (100), with the interfaces represented by intermixing profiles controlled by a single parameter, we evaluate layer-resolved shifts as a probe of the thin-film quality. The core-level shifts in the corresponding disordered alloys, as well as local environment effects, are studied for comparison. We also discuss the possibility of detecting interface states by means of core-level shift measurements.

Place, publisher, year, edition, pages
American Physical Society, 2011
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-70748 (URN)10.1103/PhysRevB.84.085431 (DOI)000294325400015 ()
Available from: 2011-09-16 Created: 2011-09-16 Last updated: 2017-12-08
Alling, B., Marten, T. & Abrikosov, I. (2010). Effect of magnetic disorder and strong electron correlations on the thermodynamics of CrN. Physical Review B. Condensed Matter and Materials Physics, 82, 184430
Open this publication in new window or tab >>Effect of magnetic disorder and strong electron correlations on the thermodynamics of CrN
2010 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 82, p. 184430-Article in journal (Refereed) Published
Abstract [en]

Two different methods for the modeling of a magnetically disordered CrN stateusing a supercell approach are investigated. They are found to give equivalentresults of the total energy, being also similar to results obtained with an effectivemedium approach. Furthermore, CrN is shown to be better described using aLDA+U framework for the treatment of electron-electron correlations as comparedto GGA or LDA calculations. Modeling the cubic paramagnetic phase with ourmodels for magnetic disorder and considering the strong electron correlations, thetemperature and pressure induced phase transitions in CrN can be explained.

Place, publisher, year, edition, pages
American institute of physics, 2010
Keywords
CrN, magnetic disorder, nitrides, LDA+U, SQS, phase transition, chromium compounds
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-60439 (URN)10.1103/PhysRevB.82.184430 (DOI)000291462500005 ()
Available from: 2010-10-13 Created: 2010-10-13 Last updated: 2017-12-12
Olovsson, W., Marten, T., Holmstrom, E., Johansson, B. & Abrikosov, I. (2010). First principle calculations of core-level binding energy and Auger kinetic energy shifts in metallic solids. Journal of Electron Spectroscopy and Related Phenomena, 178(Sp. Iss. SI), 88-99
Open this publication in new window or tab >>First principle calculations of core-level binding energy and Auger kinetic energy shifts in metallic solids
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2010 (English)In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 178, no Sp. Iss. SI, p. 88-99Article in journal (Refereed) Published
Abstract [en]

We present a brief overview of recent theoretical studies of the core-level binding energy shift (CLS) in solid metallic materials. The focus is on first principles calculations using the complete screening picture, which incorporates the initial (ground state) and final (core-ionized) state contributions of the electron photoemission process in X-ray photoelectron spectroscopy (XPS), all within density functional theory (DFT). Considering substitutionally disordered binary alloys, we demonstrate that on the one hand CLS depend on average conditions, such as volume and overall composition, while on the other hand they are sensitive to the specific local atomic environment. The possibility of employing layer resolved shifts as a tool for characterizing interface quality in fully embedded thin films is also discussed, with examples for CuNi systems. An extension of the complete screening picture to core-core-core Auger transitions is given, and new results for the influence of local environment effects on Auger kinetic energy shifts in fcc AgPd are presented.

Place, publisher, year, edition, pages
Elsevier Science B.V., Amsterdam., 2010
Keywords
Core-level shift, Disordered materials, Metallic alloys, Auger kinetic energy
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-57401 (URN)10.1016/j.elspec.2009.10.007 (DOI)000278295900006 ()
Note
Original Publication: Weine Olovsson, Tobias Marten, Erik Holmstrom, Borje Johansson and Igor Abrikosov, First principle calculations of core-level binding energy and Auger kinetic energy shifts in metallic solids, 2010, JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA, (178), Sp. Iss. SI, 88-99. http://dx.doi.org/10.1016/j.elspec.2009.10.007 Copyright: Elsevier Science B.V., Amsterdam. http://www.elsevier.com/ Available from: 2010-06-18 Created: 2010-06-18 Last updated: 2017-12-12Bibliographically approved
Alling, B., Marten, T. & Abrikosov, I. (2010). Questionable collapse of the bulk modulus in CrN [Letter to the editor]. Nature Materials, 9(4), 283-284
Open this publication in new window or tab >>Questionable collapse of the bulk modulus in CrN
2010 (English)In: Nature Materials, ISSN 1476-1122, E-ISSN 1476-4660, Vol. 9, no 4, p. 283-284Article in journal, Letter (Other academic) Published
Abstract [en]

In this comment we show that the main conclusion in a previous article, claiminga drastic increase in compressibility of CrN at the cubic to orthorhombic phasetransition, is unsupported by first-principles calculations. We show that if thecubic CrN phase is considered as a disordered magnetic material, as supported bydifferent experimental data, rather then non-magnetic, the bulk modulus is almostunaffected by the transition.

Place, publisher, year, edition, pages
London, UK: Nature Publishing Group, 2010
Keywords
CrN, phase-transition, magnetism, bulk modulus, first-principles
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-60438 (URN)10.1038/nmat2722 (DOI)000275901000002 ()
Available from: 2010-10-13 Created: 2010-10-13 Last updated: 2017-12-12Bibliographically approved
Marten, T., Isaev, E., Alling, B., Hultman, L. & Abrikosov, I. (2010). Single-monolayer SiNx embedded in TiN: A first-principles study. Physical Review B. Condensed Matter and Materials Physics, 81(21), 212102
Open this publication in new window or tab >>Single-monolayer SiNx embedded in TiN: A first-principles study
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2010 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 81, no 21, p. 212102-Article in journal (Refereed) Published
Abstract [en]

The dynamical and thermodynamic stability of a single monolayer of SiNx sandwiched isostructurally between B1-TiN(001) and (111) oriented slabs are investigated by means of density functional theory. Possible dynamical stabilization of the (001) interface, by distortion of the Si-N bonds, is considered and found to almost, but not completely, remove the phonon instabilities. The (111) interface on the other hand is found to be dynamically stable. We furthermore relax the stoichiometry degree of freedom by allowing for Si vacancies in the lattice and show that the ideal 1:1 SiN stoichiometry in both interfaces are thermodynamically unstable with respect to Si vacancy formation regardless if the system is grown under nitrogen-rich or nitrogen-poor conditions, and therefore ruling out its relevance for performance of real materials.

Place, publisher, year, edition, pages
American Physical Society, 2010
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-58256 (URN)10.1103/PhysRevB.81.212102 (DOI)000279381800001 ()
Note
Original Publication: Tobias Marten, Eyvas Isaev, Björn Alling, Lars Hultman and Igor Abrikosov, Single-monolayer SiNx embedded in TiN: A first-principles study, 2010, Physical Review B. Condensed Matter and Materials Physics, (81), 21, 212102. http://dx.doi.org/10.1103/PhysRevB.81.212102 Copyright: American Physical Society http://www.aps.org/ Available from: 2010-08-10 Created: 2010-08-09 Last updated: 2017-12-12Bibliographically approved
Marten, T. (2010). Theoretical Considerations of Local Environment Effects in Alloys. (Doctoral dissertation). Linköping: Linköping University Electronic Press
Open this publication in new window or tab >>Theoretical Considerations of Local Environment Effects in Alloys
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis is devoted to a theoretical study of local environment effects in alloys. A fundamental property of a disordered system is that all chemically equivalent atoms are different due to their different chemical environments, in contrast to an ideal periodic solid where all the atoms that occupy equivalent positions in the crystal have exactly the same physical properties. The local environment effects have been largely ignored in earlier theories of disordered systems, that is the system has been treated as a whole and average properties have been derived. Moreover, inhomogeneous systems, such as surfaces and interfaces, induce local environment effects that are not necessarily present in the bulk.

The importance and presence of local environment effects are illustrated by calculating observable physical properties in various systems. In particular, by employing the complete screening picture the effects of local environments on the core-level binding energy shifts as well as Auger shifts in random alloys are in- vestigated. This so-called disorder broadening effect has recently been observed experimentally. It is shown that there are different contributions to the disorder broadening that vary with the local chemical environment. Furthermore, the influ- ence of inhomogeneous lattice distortions on the disorder broadening of the core- level photoemission spectra are considered for systems with large size-mismatch between the alloy components.

The effects of local chemical environments on physical properties in magnetic systems are illuminated. A noticeable variation in the electronic structure, local magnetic moments and exchange parameters at different sites is obtained. This reflects the sensitivity to different chemical environments and it is shown to be of qualitative importance in the vicinity of magnetic instability.

The local environment effects due to the presence of surfaces and interfaces are also considered. The effect is explicitly studied by considering the concentration profile of a thin Ag-Pd film deposited on a Ru substrate. Two computational approaches are utilized to calculate the relative composition in each layer of the thin film as a function of temperature in a theoretically consistent way. It is shown that, opposed to the situation in the bulk, where a complete solubility between Ag and Pd takes place, a non-uniform distribution of the alloy components across the film is observed.

In another study it is investigated whether the presence of TiN interfaces changes the dynamical and thermodynamic stability of B1 SiN. Phonon calcula- tions show that TiN interfaces have a stabilization effect on the lattice dynamics. On the other hand, calculations of the Si vacancy formation energy show that the structures are unstable with respect to composition variations.

 

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2010. p. 86
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1353
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-63443 (URN)978-91-7393-285-1 (ISBN)
Public defence
2010-12-17, Planck, Fysikhuset, Campus Valla, Linköpings universitet, Linköping, 10:15 (English)
Opponent
Supervisors
Available from: 2010-12-27 Created: 2010-12-19 Last updated: 2020-02-19Bibliographically approved
Marten, T., Abrikosov, I., Olovsson, W., Johansson, B., Cole, R. J., Beamson, G., . . . Weightman, P. (2009). Suppression of disorder broadening of core-level photoelectron lines in CuAu alloys by inhomogeneous lattice distortion. Physical Review B. Condensed Matter and Materials Physics, 79(1), 012201
Open this publication in new window or tab >>Suppression of disorder broadening of core-level photoelectron lines in CuAu alloys by inhomogeneous lattice distortion
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2009 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 79, no 1, p. 012201-Article in journal (Refereed) Published
Abstract [en]

Disorder broadening of core-level binding energies is a general effect observed in random alloys, and identifies an opportunity for studying specific local environments experimentally. Here we study it in an archetypical system: face-centered-cubic Cu50Au50. While the disorder broadening is clearly detectable at Au, at Cu it is below the detection limit. We supplement experiments by a theoretical study where we model the alloy by a large supercell constructed as a special quasirandom structure and calculate binding-energy shifts at all sites in the supercell. Theory shows that the suppression of the disorder broadening at Cu results from a delicate balance between the influence of local chemical environment and inhomogeneous lattice distortions on the site-resolved core-level shifts. Surprisingly, even larger relaxation-induced shifts are observed at Au sites.

Keywords
copper alloys, core levels, electronic structure, gold alloys, photoelectron spectra
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-16832 (URN)10.1103/PhysRevB.79.012201 (DOI)
Available from: 2009-02-21 Created: 2009-02-20 Last updated: 2017-12-13Bibliographically approved
Marten, T., Hellman, O., Ruban, A. V., Olovsson, W., Kramer, C., Godowski, J. P., . . . Abrikosov, I. (2008). Double-segregation effect in AgxPd1−x /Ru(0001) thin film nanostructures. Physical Review B. Condensed Matter and Materials Physics, 77, 125406-1-125406-7
Open this publication in new window or tab >>Double-segregation effect in AgxPd1−x /Ru(0001) thin film nanostructures
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2008 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 77, p. 125406-1-125406-7Article in journal (Refereed) Published
Abstract [en]

We study the structural properties of ultrathin AgxPd1−x films on top of a Ru(0001) substrate. Effective interatomic interactions, obtained from first-principles calculations, have been used in Monte Carlo simulations to derive the distribution of the alloy components in a four-monolayer (4-ML) Ag-Pd film. Though Ag-Pd alloys show complete solubility in the bulk, the thin film geometry leads to a pronounced segregation between Ag and Pd atoms with a strong preference of Ag atoms toward the surface and Pd atoms toward the interface. The theoretical prediction of this double-segregation effect is strongly supported by photoelectron spectroscopy experiments carried out for 4-ML thin films. We also show, in an additional experiment, that even in the case where initially 1 ML Ag is buried under 6 ML Pd, the whole Ag ML segregates to the surface.

Place, publisher, year, edition, pages
APS, 2008
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-44362 (URN)10.1103/PhysRevB.77.125406 (DOI)76396 (Local ID)76396 (Archive number)76396 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-13Bibliographically approved
Alling, B., Marten, T., Abrikosov, I. & Karimi, A. (2007). Comparison of thermodynamic properties of cubic Cr 1-x Al x N and Ti 1-x Al x N from first-principles calculations. Journal of Applied Physics, 102(044314)
Open this publication in new window or tab >>Comparison of thermodynamic properties of cubic Cr 1-x Al x N and Ti 1-x Al x N from first-principles calculations
2007 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 102, no 044314Article in journal (Refereed) Published
Abstract [en]

In order to investigate the stability of the cubic phase of Cr1−xAlxN at high AlN content, first principles calculations of magnetic properties, lattice parameters, electronic structure, and mixing enthalpies of the system were performed. The mixing enthalpy was calculated on a fine concentration mesh to make possible the accurate determination of its second concentration derivative. The results are compared to calculations performed for the related compound Ti1−xAlxN and with experiments. The mixing enthalpy is discussed in the context of isostructural spinodal decomposition. It is shown that the magnetism is the key to understand the difference between the Cr- and Ti-containing systems. Cr1−xAlxN turns out to be more stable against spinodal decomposition than Ti1−xAlxN, especially for AlN-rich samples which are of interest in cutting tools applications.

Keywords
ab initio calculations, aluminium compounds, band structure, chromium compounds, enthalpy, lattice constants, magnetic materials, spinodal decomposition, titanium compounds
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-41330 (URN)10.1063/1.2773625 (DOI)55537 (Local ID)55537 (Archive number)55537 (OAI)
Note
Original Publication: Björn Alling, Tobias Marten, Igor Abrikosov and A. Karimi, Comparison of thermodynamic properties of cubic Cr1-x Alx N and Ti1-x Alx N from first-principles calculations, 2007, Journal of Applied Physics, (102), 044314. http://dx.doi.org/10.1063/1.2773625 Copyright: American Institute of Physics http://www.aip.org/ Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-13
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