Unusual Conductance Fluctuations and Quantum Oscillation in Mesoscopic Topological Insulator PbBi4Te7
Unusual Conductance Fluctuations and Quantum Oscillation in Mesoscopic Topological Insulator PbBi4Te7
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DOI：
10.1038/s41598-019-43534-7
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发表时间：
2019-05
影响因子：
4.6
通讯作者：
P. Mal;B. Das;A. Lakhani;G. Bera;G. R. Turpu;J. Wu;C. V. Tomy;P. Das
中科院分区：
文献类型：
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作者：
P. Mal;B. Das;A. Lakhani;G. Bera;G. R. Turpu;J. Wu;C. V. Tomy;P. Das
我们详细研究了介观拓扑绝缘体pbbi4te7器件中伴随电导波动的Shubinikov-de-Haas （SdH）振荡。从SdH振荡中发现了具有π berry相的狄拉克费米子存在的证据，实验确定的两个主要费米波矢量与层状拓扑绝缘体PbBi4Te7的两个表面狄拉克锥（一个埋在另一个里面）相关。我们还发现了电导波动的证据，其均方根振幅远高于通常在纳米尺寸样品中观察到的普遍电导波动。计算的自相关函数表明，周期性的唯一波动可能与化合物的拓扑表面状态有关。
We present a detail study of Shubinikov-de-Haas (SdH) oscillations accompanied by conductance fluctuations in a mesoscopic topological insulator PbBi4Te7device. From SdH oscillations, the evidence of Dirac fermions withπBerry phase is found and the experimentally determined two main Fermi wave vectors are correlated to two surface Dirac cones (buried one inside the other) of layered topological insulator PbBi4Te7. We have also found evidence of conductance fluctuations, the root mean square amplitude of which is much higher than the usual universal conductance fluctuations observed in nanometer size sample. Calculated autocorrelation functions indicate periodic unique fluctuations may be associated with the topological surface states in the compound.