Antiferromagnetic order competing with topological state in CexBi2-xTe3

作者：Lee H S; Kim J; Lee K; Jelen A; Vrtnik S; Jaglicic Z; Dolinsek J; Jung M H^*

来源：Applied Physics Letters, 2015, 107(18): 182409.

DOI：10.1063/1.4935120

The topological surface states in three-dimensional topological insulators are easily tuned by chemical doping, especially by magnetic impurities. We prepared single crystals of CexBi2-xTe3 with various x (=0.04, 0.06, 0.08, 0.10, and 0.12). The obtained crystals were characterized by X-ray diffraction and scanning electron microscopy. The magnetic susceptibility data revealed that the Ce atoms are well substituted for Bi into Bi2Te3. From the Curie-Weiss fits, we observed that the effective magnetic moments mu(eff) are close to 2.54 mu B for free Ce ion, and the paramagnetic Curie-Weiss temperatures theta(p) are negatively increased from 2.87 K to -59.3 K with increasing x. The magnetization data clearly showed antiferromagnetic orders around T-N = 4.1 K for x >= 0.08, where theta(p) suddenly increases, and the electrical resistivity is simply metallic and the magnetoresistance is parabolic. Only for x = 0.06, exotic physical properties arising from the topological states were observed such as non-metallic behavior in the electrical resistivity and linear dependence of the magnetoresistance. Moreover, the carrier concentration of x = 0.06 is one order lower than that of x >= 0.08. These observations propose that the antiferromagnetic order is strongly competing with the topological state in CexBi(2-x)Te(3).

• 出版日期2015-11-2