Indications of surface-dominated transport in single crystalline nanoflake devices of topological insulator Bi1.5Sb0.5Te1.8Se1.2
Indications of surface-dominated transport in single crystalline nanoflake devices of topological insulator Bi1.5Sb0.5Te1.8Se1.2
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DOI：
10.1103/physrevb.87.085442
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发表时间：
2013-02-27
影响因子：
3.7
通讯作者：
Wang, Lan
中科院分区：
文献类型：
--
作者：
Xia, Bin;Ren, Peng;Wang, Lan
我们报道了拓扑绝缘体Bi1.5Sb0.5Te1.8Se1.2 （BSTS）单晶纳米片器件中表面主导输运的实验证据。电阻率测量结果表明，纳米片器件与块状单晶器件存在显著差异。基于双通道模型，对电阻率和霍尔电阻的分析表明，在200 nm厚的BSTS纳米片器件中，可以实现接近99%的表面输运贡献。采用以SiO2为介电层的标准后门，在100- 200nm厚片的器件中观察到明显的双极电场效应。此外，对厚度为596纳米片器件的角相关磁电阻进行了拟合，得到了外加磁场垂直分量的通用曲线。二维弱反局域拟合得到的相相干长度进一步证实了表面主导输运。我们的研究结果为基于拓扑螺旋表面态的电子和自旋电子器件的实现开辟了道路。DOI: 10.1103 / PhysRevB.87.085442
We report experimental evidence of surface-dominated transport in single crystalline nanoflake devices of topological insulator Bi1.5Sb0.5Te1.8Se1.2 (BSTS). The resistivity measurements show dramatic differences between the nanoflake devices and bulk single crystal. Based on a two-channel model, the analysis on the resistivity and Hall resistance indicates that similar to 99% surface transport contribution can be realized in 200 nm-thick BSTS nanoflake devices. Using a standard back gate with SiO2 as a dielectric layer, a pronounced ambipolar electric field effect was observed in devices fabricated with 100-200 nm thick flakes. Moreover, angle-dependent magnetoresistances of a nanoflake device with a thickness of 596 nanometers are fitted to a universal curve for the perpendicular component of the applied magnetic field. The value of phase coherence length obtained from two-dimensional weak antilocalization fitting further confirmed the surface dominated transport. Our results open a path for realization of electric and spintronic devices based on the topological helical surface states. DOI: 10.1103/PhysRevB.87.085442