Issue
EPL
Volume 83, Number 6, September 2008
Article Number 69001
Number of page(s) 5
Section Geophysics, Astronomy and Astrophysics
DOI http://dx.doi.org/10.1209/0295-5075/83/69001
Published online 05 September 2008
EPL, 83 (2008) 69001
DOI: 10.1209/0295-5075/83/69001

Electronic structure and magnetism of EuX (X = O, S, Se and Te): A first-principles investigation

S. Q. Shi1, 2, C. Y. Ouyang3, Q. Fang3, J. Q. Shen1, W. H. Tang1 and C. R. Li1

1   Department of Physics, Center for Optoelectronics Materials and Devices, Zhejiang Sci-Tech University, Xiasha College Park - Hangzhou 310018, China
2   State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences - Shanghai 200050, China
3   Department of electronics, Jiangxi University of Finance and Economy - Nanchang 330013, China

siqishi@yahoo.com

received 1 May 2008; accepted in final form 24 July 2008; published September 2008
published online 5 September 2008

Abstract
Electronic structures and magnetic properties of EuX (X = O, S, Se and Te) are investigated by the plane-wave pseudopotential method with explicit account for Coulomb repulsion within the 4f shell, and compared with other theoretical and experimental results. All the EuX compounds are magnetic semiconductors with noticeable indirect $\Gamma $-X gap. Ferromagnetic ordering is observed for EuO and EuS while antiferromagnetic ordering along [111] is the ground state for EuSe and EuTe. These results are consistent with the experiments, although previous calculations indicated that the ground state of EuS is antiferromagnetic. The exchange parameters are calculated, and are in fair agreement with experimental results.

PACS
91.60.Pn - Magnetic and electrical properties.
31.15.aq - Strongly correlated electron systems: generalized tight-binding method.
77.84.Bw - Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.

© EPLA 2008