論文

査読有り
2014年3月

Triplet ground state of the neutral oxygen-vacancy donor in rutile TiO2

PHYSICAL REVIEW B
  • A. T. Brant
  • ,
  • E. M. Golden
  • ,
  • N. C. Giles
  • ,
  • Shan Yang
  • ,
  • M. A. R. Sarker
  • ,
  • S. Watauchi
  • ,
  • M. Nagao
  • ,
  • I. Tanaka
  • ,
  • D. A. Tryk
  • ,
  • A. Manivannan
  • ,
  • L. E. Halliburton

89
11
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1103/PhysRevB.89.115206
出版者・発行元
AMER PHYSICAL SOC

Electron paramagnetic resonance (EPR) is used to investigate the triplet (S = 1) ground state of the neutral oxygen vacancy in bulk rutile TiO2 crystals. This shallow donor consists of an oxygen vacancy with two nearest-neighbor, exchange-coupled Ti3+ ions located along the [001] direction and equidistant from the vacancy. The spins of the two trapped electrons, one at each Ti3+ ion, align parallel to give the S = 1 state. These neutral oxygen vacancies are formed near 25 K in as-grown oxidized TiO2 crystals by illuminating with sub-band-gap 442 nm laser light. The angular dependence of the EPR spectra provides the principal values and axes for the g and D matrices. Observations of the Ti-47 and Ti-49 hyperfine lines when the magnetic field is along high-symmetry directions show that the two Ti3+ ions are equivalent; i.e., they have equal hyperfine A matrices. The A matrix for each Ti3+ ion in the neutral S = 1 oxygen vacancy is approximately half of the A matrix reported earlier for the one Ti3+ ion in the singly ionized S = 1/2 oxygen vacancy [Brant et al., J. Appl. Phys. 114, 113702 (2013)]. The neutral oxygen vacancies are thermally unstable above 25 K. They release an electron to the conduction band with an activation energy near 63 meV and convert to singly ionized S = 1/2 oxygen vacancies. When undoped TiO2 is sufficiently oxygen deficient (i.e., reduced), this combination of conduction band electrons and singly ionized oxygen vacancies may result in carrier-mediated ferromagnetism at room temperature.

Web of Science ® 被引用回数 : 15

リンク情報
DOI
https://doi.org/10.1103/PhysRevB.89.115206
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000333554600002&DestApp=WOS_CPL
URL
http://www.scopus.com/inward/record.url?eid=2-s2.0-84898722235&partnerID=MN8TOARS
URL
http://orcid.org/0000-0003-4660-9674

エクスポート
BibTeX RIS