A density functional theory investigation of the electronic structure and spin moments of magnetite

Junghyun Noh, Osman I. Osman, Saadullah G. Aziz, Paul Winget, Jean Luc Brédas

Research output: Contribution to journalArticlepeer-review

66 Scopus citations

Abstract

We present the results of density functional theory (DFT) calculations on magnetite, Fe3O4, which has been recently considered as electrode in the emerging field of organic spintronics. Given the nature of the potential applications, we evaluated the magnetite room-temperature cubic phase in terms of structural, electronic, and magnetic properties. We considered GGA (PBE), GGA + U (PBE + U), and range-separated hybrid (HSE06 and HSE(15%)) functionals. Calculations using HSE06 and HSE(15%) functionals underline the impact that inclusion of exact exchange has on the electronic structure. While the modulation of the band gap with exact exchange has been seen in numerous situations, the dramatic change in the valence band nature and states near the Fermi level has major implications for even a qualitative interpretation of the DFT results. We find that HSE06 leads to highly localized states below the Fermi level while HSE(15%) and PBE + U result in delocalized states around the Fermi level. The significant differences in local magnetic moments and atomic charges indicate that describing room-temperature bulk materials, surfaces and interfaces may require different functionals than their low-temperature counterparts.

Original languageEnglish (US)
Article number044202
JournalScience and Technology of Advanced Materials
Volume15
Issue number4
DOIs
StatePublished - Aug 1 2014
Externally publishedYes

Keywords

  • DFT
  • ferrimagnetism
  • inverse spinel structure
  • magnetite
  • spintronics

ASJC Scopus subject areas

  • Materials Science(all)

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