liu.seSearch for publications in DiVA
Endre søk
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Phase stability of the nanonlaminates V2Ga2C and (Mo1-xVx)2Ga2C from first-principles calculations
Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.ORCID-id: 0000-0001-5036-2833
Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
2016 (engelsk)Manuskript (preprint) (Annet vitenskapelig)
Abstract [en]

We here use first-principles calculations to investigate the phase stability of the hypothetical laminated materials V2Ga2C and the related alloy (Mo1-xVx)2Ga2C, the latter for a potential parent material for synthesis of (Mo1-xVx)2C, a new two-dimensional material in the family of so called MXenes. We predict that V2Ga2C is thermodynamically stable with respect to all identified competing phases in the ternary VGa-C phase diagram. We further predict the stability for ordered and disordered configurations of Mo and V in (Mo1-xVx)2Ga2C and predict that ordered (Mo1-xVx)2Ga2C for 𝑥 ≤ 0.25 is stable, with an orderdisorder transition temperature of ~1000 K. Furthermore, (Mo1-xVx)2Ga2C for 𝑥 = 0.5 and 𝑥 ≥ 0.75 is suggested to potentially be stable, but only for disordered Mo-V configurations, and only at elevated temperatures. We have also investigated the electronic and elastic properties of V2Ga2C; the calculated bulk, shear, and Young’s modulus are 141, 95, and 232 GPa, respectively.

sted, utgiver, år, opplag, sider
2016. s. 51-
HSV kategori
Identifikatorer
URN: urn:nbn:se:liu:diva-124561OAI: oai:DiVA.org:liu-124561DiVA, id: diva2:900112
Tilgjengelig fra: 2016-02-03 Laget: 2016-02-03 Sist oppdatert: 2017-11-03bibliografisk kontrollert
Inngår i avhandling
1. Phase stability and physical properties of nanolaminated materials from first principles
Åpne denne publikasjonen i ny fane eller vindu >>Phase stability and physical properties of nanolaminated materials from first principles
2016 (engelsk)Doktoravhandling, med artikler (Annet vitenskapelig)
Abstract [en]

The MAX phase family is a set of nanolaminated, hexagonal materials typically comprised of three elements: a transition metal (M), an A-group element (A), and carbon and/or nitrogen (X). In this thesis, first-principles based methods have been used to investigate the phase stability and physical properties of a number of MAX and MAX-like phases.

Most theoretical work on MAX phase stability use the constraint of 0 K conditions, due to the very high computational cost of including temperature dependent effects such as lattice vibrations and electronic excitations for all relevant competing phases in the ternary or multinary chemical space. Despite this, previous predictions of the existence of new MAX phases have to a large extent been experimentally verified. In an attempt to provide a possible explanation for this consistency, and thus help strengthen the confidence in future predictions, we have calculated the temperature dependent phase stability of Tin+1AlCn, to date the most studied MAX phases. We show that both the electronic and vibrational contribution to the Gibbs free energies of the MAX phases are  cancelled by the corresponding contributions to the Gibbs free energies of the competing phases. We further show that this is the case even when thermal expansion is considered.

We have also investigated the stability of two hypothetical MAX-like phases, V2Ga2C and (Mo1-xVx)2Ga2C, motivated by a search for ways to attain new two-dimensional MAX phase derivatives, so-called MXenes. We predict that it is possible to synthesize both phases. For x≤0.25, stability of (Mo1-xVx)2Ga2C is indicated for both ordered and disordered solid solutions on the M sublattice. For x=0.5 and x≥0.75, stability is only indicated for disordered solutions. The ordered solutions are stable at temperatures below 1000 K, whereas stabilization of the disordered solutions requires temperatures of up to 2100 K, depending on the V concentration.

Finally, we have investigated the electronic, vibrational, and magnetic properties of the recently synthesized MAX phase Mn2GaC. We show that the electronic band structure is anisotropic, and determine the bulk, shear, and Young’s modulus to be 157, 93, and 233 GPa, respectively, and Poisson’s ratio to be 0.25. We further predict the magnetic critical order-disorder temperature of Mn2GaC to be 660 K. We base the predictions on Monte Carlo simulations of a bilinear Heisenberg Hamiltonian constructed from magnetic exchange interaction parameters derived using two different supercell methods: the novel magnetic direct cluster averaging method (MDCA), and the Connolly-Williams method (CW). We conclude that CW is less computationally expensive than MDCA for chemically and topologically ordered phases such as Mn2GaC.

sted, utgiver, år, opplag, sider
Linköping: Linköping University Electronic Press, 2016. s. 57
Serie
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1742
HSV kategori
Identifikatorer
urn:nbn:se:liu:diva-124564 (URN)10.3384/diss.diva-124564 (DOI)978-91-7685-835-6 (ISBN)
Disputas
2016-03-04, Planck, Fysikhuset, Campus Valla, Linköping, 09:30 (engelsk)
Opponent
Veileder
Tilgjengelig fra: 2016-02-03 Laget: 2016-02-03 Sist oppdatert: 2017-11-03bibliografisk kontrollert

Open Access i DiVA

Fulltekst mangler i DiVA

Personposter BETA

Thore, AndreasDahlqvist, MartinAlling, BjörnRosén, Johanna

Søk i DiVA

Av forfatter/redaktør
Thore, AndreasDahlqvist, MartinAlling, BjörnRosén, Johanna
Av organisasjonen

Søk utenfor DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric

urn-nbn
Totalt: 259 treff
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf