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- Cherian, R., et al.
(författare)
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Role of Coulomb interactions in semicore levels Ga d levels of GaX semiconductors : Implication on band offsets
- 2009
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Ingår i: Solid State Communications. - : Elsevier BV. - 0038-1098 .- 1879-2766. ; 149:41-42, s. 1810-1813
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Tidskriftsartikel (refereegranskat)abstract
- The positions of the semicore Ga d levels in GaX semiconductors (X = N, P, and As) are underestimated in density functional calculations using either the local density approximation LIDA or the generalized gradient approximation GGA for the exchange functional. Correcting for this inaccuracy within LDA + U calculations with an on-site Coulumb interaction U on the semicore d-states results in a modest enhancement of the band gap. We show that this modest enhancement of the band-gap energy comes from the movement of the valence-band maximum alone, thus not affecting the conduction-band states. Further, the localization of the charge on Ga d states with U leads to a regulation of charge on Ga. This yields a shift of 1-2 eV of the core levels on the Ga atom while the anion core levels remain unchanged.
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| 3. |
- Cherian, R., et al.
(författare)
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Trends in ferromagnetism in Mn-doped dilute III-V alloys from a density functional perspective
- 2009
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 79:19
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Tidskriftsartikel (refereegranskat)abstract
- Mn doping in dilute III-V alloys has been examined as a route to enhance ferromagnetic stability. Strong valence-band bowing is expected at the dilute limit, implying a strong modification of the ferromagnetic stability upon alloying with even an increase in some cases. Using first-principles electronic structure calculations we show that while codoping with a group V anion enhances the ferromagnetic stability in some cases when the effects of relaxation of the lattice are not considered, strong impurity scattering in the relaxed structure result in a reduction in the ferromagnetic stability.
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