Issue
EPL
Volume 81, Number 1, January 2008
Article Number 17004
Number of page(s) 4
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
DOI http://dx.doi.org/10.1209/0295-5075/81/17004
Published online 20 November 2007
EPL, 81 (2008) 17004
DOI: 10.1209/0295-5075/81/17004

Origin of unexpected magnetism in Cu-doped TiO2

Q. K. Li1, B. Wang1, 2, C. H. Woo3, H. Wang1, Z. Y. Zhu1 and R. Wang4

1  School of Astronautics, Harbin Institute of Technology - West Da-Zhi Street, No. 92, Harbin, China
2  School of Physics and Engineering, SUN-YAT SEN University - GuangZhou, China
3  Department of Electronic and Information Engineering, Hong Kong Polytechnic University - Hung Hom, Kowloon, HongKong
4  Department of Applied Chemistry, Harbin Institute of Technology - West Da-Zhi Street, No. 92, Harbin, China


received 10 June 2007; accepted in final form 28 October 2007; published January 2008
published online 20 November 2007

Abstract
Cu-doped TiO2 has recently been found to exhibit unexpected room temperature ferromagnetism. In the present work, possible defect structures and the associated magnetism are calculated within the generalized gradient approximation using the projector augmented wave method (PAW). In particular, structures of the vacancy-Cu impurity complex are studied. Our results show that the magnetism is caused by: 1) the hybridization of p-d orbitals between the Cu and O ions, and 2) the spin polarization of the 3d orbital of Cu and of the 2p orbital of O ions.

PACS
71.15.Mb - Density functional theory, local density approximation, gradient and other corrections.
61.72.Ji - Point defects (vacancies, interstitials, color centers, etc.) and defect clusters.
75.50.Pp - Magnetic semiconductors.

© EPLA 2008