High-Mobility Sm-Doped Bi2 Se3 Ferromagnetic Topological Insulators and Robust Exchange Coupling

Taishi Chen; Wenqing Liu; Fubao Zheng; Ming Gao; Xingchen Pan; Gerrit van der Laan; Xuefeng Wang; Qinfang Zhang; Fengqi Song; Baigeng Wang; Baolin Wang; Yongbing Xu; Guanghou Wang; Rong Zhang

doi:10.1002/adma.201501254

High-Mobility Sm-Doped Bi2 Se3 Ferromagnetic Topological Insulators and Robust Exchange Coupling

Adv Mater. 2015 Sep 2;27(33):4823-9. doi: 10.1002/adma.201501254. Epub 2015 Jul 14.

Authors

Taishi Chen^{1

2}, Wenqing Liu^{1

3

4}, Fubao Zheng⁵, Ming Gao^{1

3}, Xingchen Pan^{1

2}, Gerrit van der Laan⁶, Xuefeng Wang^{1

3}, Qinfang Zhang⁵, Fengqi Song^{1

2}, Baigeng Wang^{1

2}, Baolin Wang⁵, Yongbing Xu^{1

3

4}, Guanghou Wang^{1

2}, Rong Zhang^{1

3}

Affiliations

¹ Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructures, Nanjing University, Nanjing, 210093, P. R. China.
² Department of Physics, Nanjing University, Nanjing, 210093, P. R. China.
³ School of Electronic Science and Engineering, Nanjing University, Nanjing, 210093, P. R. China.
⁴ Department of Electronics, University of York, York, YO10 5DD, UK.
⁵ Key Laboratory for Advanced Technology in Environmental Protection of Jiangsu Province, Yancheng Institute of Technology, Yancheng, 224051, P. R. China.
⁶ Diamond Light Source, Didcot, OX11 0DE, UK.

PMID: 26178149
DOI: 10.1002/adma.201501254

Abstract

High-mobility (Smx Bi1-x )2 Se3 topological insulators (with x = 0.05) show a Curie temperature of about 52 K, and the carrier concentration and Fermi wave vector can be manipulated by intentional Te introduction with no significant influence on the Curie temperature. The origin of the ferromagnetism is attributed to the trivalent Sm dopant, as confirmed by X-ray magnetic circular dichroism and first-principles calculations. The carrier concentration is on the order of 10(19) cm(-3) and the mobility can reach about 7200 cm(2) V(-1) s(-1) with pronounced Shubnikov-de Haas oscillations.

Keywords: X-ray magnetic circular dichroism (XMCD); dilute magnetic semiconductors; ferromagnetism; magnetic doping; topological insulators.