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Energetics and magn...
Energetics and magnetic properties of V-doped MgO bulk and (001) surface : A GGA, GGA+U, and hybrid density functional study
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- Århammar, Cecilia (författare)
- Uppsala universitet,KTH,Tillämpad materialfysik,Materialteori
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- Araujo, C. Moyses (författare)
- KTH,Tillämpad materialfysik
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- Rao, K. Venkat (författare)
- KTH,Tillämpad materialfysik
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Norgren, S. (författare)
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- Johansson, Börje (författare)
- Uppsala universitet,KTH,Tillämpad materialfysik,Materialteori
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- Ahuja, Rajeev (författare)
- Uppsala universitet,KTH,Tillämpad materialfysik,Materialteori
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(creator_code:org_t)
- 2010
- 2010
- Engelska.
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 82:13, s. 134406-
- Relaterad länk:
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https://urn.kb.se/re...
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https://doi.org/10.1...
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https://urn.kb.se/re...
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Abstract
Ämnesord
Stäng
- In this work, a first-principles study of the energetic and magnetic properties of V-doped MgO is presented, where both the bulk and (001) surface were investigated. It is found that V assumes a high-spin state with a local moment of about 3 mu(B). In the bulk, the interaction between these local moments is very short ranged and the antiferromagnetic (AFM) ordering is energetically more favorable. The formation of V-V-Mg-V defect clusters is found to weaken the antiferromagnetic coupling in bulk MgO, degenerating the AFM and ferro-magnetic state. However, these clusters are high in energy and will not form at equilibrium conditions. By employing the GGA+U approach, with U=5 eV, the V 3d states on the (001) surface are shifted below the Fermi level, and a reasonable surface geometry was achieved. A calculation with the hybrid HSE03 functional, contradicts the GGA+U results, indicating that the V-MgO surface should be metallic at this concentration. From the energetics it is concluded that, at the modeled concentration, VxOy phases will limit the solubility of V in MgO at equilibrium conditions, which is in agreement with previous experimental findings. In order to achieve higher concentrations of V, an off-equilibrium synthesis method is needed. Finally, we find that the formation energy of V at the surface is considerably higher than in the bulk and V is thus expected to diffuse from the surface into the bulk of MgO.
Ämnesord
- NATURVETENSKAP -- Fysik -- Den kondenserade materiens fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Condensed Matter Physics (hsv//eng)
- NATURVETENSKAP -- Fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences (hsv//eng)
Nyckelord
- Condensed matter physics
- Kondenserade materiens fysik
- Physics
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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