Azat Sulaev, Peng Ren, Bin Xia, Qing Hua Lin, Zhi Peng Li, Wei Guang Zhu, Ming Yong Han, Shun-Qing Shen, Lan Wang
We show the first experimental evidence of topological surface states in Beta-Ag2Te through periodic quantum interference effect. The coexistence of pronounced Aharonov-Bohm oscillations and weak Altshuler-Aronov-Spivak oscillations clear demonstrates that coherent electron transport around the perimeter of Beta-Ag2Te nanoplate and therefore the existence of robust topological surface states. The existence of surface states is further supported by the temperature dependence of resistivity for Beta-Ag2Te nanoplates with different cross section areas. Moreover, by comparing the temperature dependent magnetoresistance of two single crystalline Beta-Ag2Te nanoplates with different cross section areas and the results of polycrystalline samples in literatures, we propose that the linear colossal magnetoresistance of Beta-Ag2Te may mainly come from the bulk. The analysis on angular dependent magnetoresistance of Beta-Ag2Te indicates that linear magnetoresistance and two dimension magnetoresistance behavior may not secure a surface state. The coexistence of colossal magnetoresistance and topological helical surface in Beta-Ag2Te suggests a promising material for fundamental study and future spintronic devices.
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http://arxiv.org/abs/1204.3816
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