Time-dependent electrical transport properties of topological insulator Cr-doped Bi2Se3 thin films
Time-dependent electrical transport properties of topological insulator Cr-doped Bi2Se3 thin films
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拓扑绝缘体 Cr 掺杂 Bi2Se3 薄膜随时间变化的电传输特性
DOI：
10.1002/pssb.201800735
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Gao Kuang Hong
中科院分区：
文献类型：
--
作者：
Li Qiu Lin;Zhang Xing Hua;Wang Wen Jie;Li Zhi Qing;Zhou Ding Bang;Gao Kuang Hong
研究了Cr掺杂Bi 2Se 3薄膜的电输运性质。具有均匀Cr分布的薄膜呈现出与未掺杂的Bi_2Se_3薄膜相同的结构。在低温下，观察到弱反局域化（WAL）和电子-电子相互作用（EEI）效应。从WAL效应中提取了失相长度和输运通道数。所提取的退相长度的温度依赖性可以通过奈奎斯特电子-电子散射和电子-声子散射来描述。随着真空时间的增加，薄膜的电阻表现出从负到正的温度系数的转变，随着电子密度的增加。出乎意料的是，从WAL效应中提取的传输通道数量随着时间的增加而增加，这一点通过分析EEI效应得到了进一步证实。这一观察结果可以归因于薄膜表面上存在二维电子气，这可能是通过与水的表面反应形成的。
This paper reports the research of the electrical transport properties of Cr‐doped Bi2Se3thin films. The films with a uniform Cr distribution exhibit the same structure as undoped Bi2Se3thin film. At low temperatures, both the weak antilocalization (WAL) and the electron–electron interaction (EEI) effects are observed. From the WAL effect, the dephasing length and the number of the transport channels are extracted. The temperature dependence of the extracted dephasing length can be described by both the Nyquist electron–electron and the electron–phonon scatterings. With increasing time in vacuum, the resistances of the thin films exhibit a transition from the negative to the positive temperature coefficient, with an increase in electron density. Unexpectedly, the number of the transport channels extracted from the WAL effect is found to increase with increasing time, which is further confirmed by analyzing the EEI effect. This observation can be attributed to the presence of two‐dimensional electron gas on the surface of films, which is likely to be formed through the surface reaction with water.