Thickness-Independent Transport Channels in Topological Insulator Bi2Se3 Thin Films
Thickness-Independent Transport Channels in Topological Insulator Bi2Se3 Thin Films
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DOI：
10.1103/physrevlett.109.116804
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发表时间：
2012-09-12
影响因子：
8.6
通讯作者：
Oh, Seongshik
中科院分区：
文献类型：
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作者：
Bansal, Namrata;Kim, Yong Seung;Oh, Seongshik
高品质的拓扑绝缘体Bi 2Se 3薄膜，我们报告的厚度无关的输运性质在很宽的厚度范围内。当样品厚度从256变化到类似于8 QL（其中QL是指五重层，1 QL近似于1 nm）时，电导保持标称恒定。确定了两个非常不同的行为的表面通道。一个通道的片状载流子密度保持恒定，近似于3.0 × 10（13）cm（-2），低至2 QL，而另一个通道表现出量子振荡，保持恒定，近似于8 × 10（12）cm（-2），仅低至近似于8 QL。弱反定域化参数也表现出类似的厚度无关性。这两个通道分别与拓扑表面态和表面积累层最一致。
With high quality topological insulator Bi2Se3 thin films, we report thickness-independent transport properties over wide thickness ranges. Conductance remained nominally constant as the sample thickness changed from 256 to similar to 8 QL(where QL refers to quintuple layer, 1 QL approximate to 1 nm). Two surface channels of very different behaviors were identified. The sheet carrier density of one channel remained constant at similar to 3.0 X 10(13) cm(-2) down to 2 QL, while the other, which exhibited quantum oscillations, remained constant at similar to 8 X 10(12) cm(-2) only down to similar to 8 QL. The weak antilocalization parameters also exhibited similar thickness independence. These two channels are most consistent with the topological surface states and the surface accumulation layers, respectively.