Vacancy-enhanced ferromagnetism in Fe-doped rutile Ti O 2
2006; American Physical Society; Volume: 74; Issue: 23 Linguagem: Inglês
10.1103/physrevb.74.235207
ISSN1550-235X
AutoresJun Chen, Paul Rulis, Lizhi Ouyang, S. Satpathy, W. Y. Ching,
Tópico(s)Advanced Condensed Matter Physics
ResumoBased on a series of supercell density functional calculations of Fe-doped $\mathrm{Ti}{\mathrm{O}}_{2}$ both with and without O vacancy $({V}_{\mathrm{O}})$, we show that ${V}_{\mathrm{O}}$ plays an important role in determining the magnetic properties of the dilute magnetic semiconductors (DMS). Without ${V}_{\mathrm{O}}$, two Fe atoms in rutile lattice are ferromagnetically coupled except at a separation distance of $3.57\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$, where they are antiferromagnetically coupled. The ${V}_{\mathrm{O}}$ introduces two electrons into the conduction bands of rutile, which are either captured by the Fe dopants or form a shallow impurity state. The ferromagnetic (FM) coupling $J$ between two Fe atoms is enhanced, through the enhancement of the FM double exchange if ${V}_{\mathrm{O}}$ is sufficiently close.
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