Defect compensation, clustering, and magnetism in Cr-doped anatase Ti O2

Lin Hui Ye, Arthur J Freeman

Research output: Contribution to journalArticle

73 Citations (Scopus)

Abstract

The origin of the magnetism in recently reported Cr doped anatase Ti O2 is investigated with first principles full-potential linearized augmented plane wave calculations. Through a systematic study over a range of defect compensation, we predict a strikingly different behavior of Cr3+ (compensated species) and Cr4+ (noncompensated species): Cr3+ tends to distribute uniformly but contributes only to paramagnetism. By contrast, Cr4+ tends to form clusters which induces strong ferromagnetism. The same p-d hopping interaction found in Mn:GaAs also explains the presence or absence of ferromagnetism and its dependence on the compensation; this short-range bonding interaction is also one of the major sources for the predicted clustering of Cr4+. Our results thus contradict the experimental interpretation that oxygen vacancies induced the ferromagnetic coupling between Cr3+ through the F-center bound magnetic polaron (FCBMP) mechanism. We show that large size magnetic polarons cannot form in Cr:Ti O2 and that the FCBMP mechanism does not apply.

Original languageEnglish
Article number081304
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume73
Issue number8
DOIs
Publication statusPublished - 2006

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Gene Conversion
Ferromagnetism
Magnetism
color centers
anatase
Titanium dioxide
ferromagnetism
Paramagnetism
Polarons
Defects
paramagnetism
defects
polarons
Oxygen vacancies
plane waves
interactions
oxygen
Compensation and Redress
titanium dioxide
gallium arsenide

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Defect compensation, clustering, and magnetism in Cr-doped anatase Ti O2. / Ye, Lin Hui; Freeman, Arthur J.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 73, No. 8, 081304, 2006.

Research output: Contribution to journalArticle

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