Abstract
There are many interests to achieve long-range magnetic order in topological insulators of Bi2Se3 or Bi2Te3 by doping magnetic transition metals such as Fe and Mn. The transition metals act as not only magnetic dopants but also electric dopants because they are usually divalent. However, if the doping elements are rare-earth metals such as Gd, which are trivalent, only magnetic moments can be introduced. We fabricated single crystals of Bi2-xGdxTe3 (0 ≤ × ≤ 0.2), in which we observed magnetic phase change from paramagnetic (PM) to antiferromagnetic (AFM) phase by increasing x. This PM-to-AFM phase transition agrees with the density functional theory calculations showing a weak and short-ranged Gd-Gd AFM coupling via the intervening Te ions. The critical point corresponding to the magnetic phase transition is x = 0.09, where large linear magnetoresistance and highly anisotropic Shubnikov-de Haas oscillations are observed. These results are discussed with two-dimensional properties of topological surface state electrons.
Highlights
The spin-momentum locked surface states of three-dimensional (3D) topological insulators (TIs) are protected by time reversal symmetry (TRS)[1,2,3,4,5]
One theoretical paper proposed that the single quintuple layer of GdBiTe3 film can be a quantum anomalous Hall (QAH) insulator with ferromagnetic ordering, and the gapless chiral edge states exist inside the bulk band gap[15]
The samples of Bi2-xGdxTe3 were characterized by X-ray diffraction (XRD) patterns
Summary
The spin-momentum locked surface states of three-dimensional (3D) topological insulators (TIs) are protected by time reversal symmetry (TRS)[1,2,3,4,5]. Several papers reported that the magnetic impurities such as Fe or Mn can break the TRS and affect the gapless surface states, leading to a gap opening[11,12,13,14]. Such magnetic impurities induce electrical doping effect at the same time, i.e., the charge carriers are doped. The substitution of Bi by Gd may maximize the magnetic doping effect on TIs. One theoretical paper proposed that the single quintuple layer of GdBiTe3 film can be a QAH insulator with ferromagnetic ordering, and the gapless chiral edge states exist inside the bulk band gap[15].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
