Role of Coulomb interactions in semicore levels Ga d levels of GaX semiconductors: Implication on band offsets
2009 (English)In: Solid State Communications, ISSN 0038-1098, E-ISSN 1879-2766, Vol. 149, no 41-42, 1810-1813 p.Article in journal (Refereed) Published
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.
Place, publisher, year, edition, pages
2009. Vol. 149, no 41-42, 1810-1813 p.
Semiconductors, Electronic band structure, augmented-wave method, electronic-structure, energy, spectra, gw
IdentifiersURN: urn:nbn:se:kth:diva-18859DOI: 10.1016/j.ssc.2009.07.014ISI: 000270690000019ScopusID: 2-s2.0-69949142936OAI: oai:DiVA.org:kth-18859DiVA: diva2:336906
QC 201005252010-08-052010-08-052010-12-17Bibliographically approved