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Interface-Dominated Topological Transport in Nanograined Bulk Bi2Te3
Small ( IF 13.0 ) Pub Date : 2021-09-21 , DOI: 10.1002/smll.202103281 Sepideh Izadi 1, 2 , Jeong Woo Han 3 , Sarah Salloum 4 , Ulrike Wolff 2 , Lauritz Schnatmann 1, 2, 5 , Aswin Asaithambi 3 , Sebastian Matschy 3 , Heike Schlörb 2 , Heiko Reith 2 , Nicolas Perez 2 , Kornelius Nielsch 2, 5, 6 , Stephan Schulz 4 , Martin Mittendorff 3 , Gabi Schierning 1
Small ( IF 13.0 ) Pub Date : 2021-09-21 , DOI: 10.1002/smll.202103281 Sepideh Izadi 1, 2 , Jeong Woo Han 3 , Sarah Salloum 4 , Ulrike Wolff 2 , Lauritz Schnatmann 1, 2, 5 , Aswin Asaithambi 3 , Sebastian Matschy 3 , Heike Schlörb 2 , Heiko Reith 2 , Nicolas Perez 2 , Kornelius Nielsch 2, 5, 6 , Stephan Schulz 4 , Martin Mittendorff 3 , Gabi Schierning 1
Affiliation
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3D topological insulators (TI) host surface carriers with extremely high mobility. However, their transport properties are typically dominated by bulk carriers that outnumber the surface carriers by orders of magnitude. A strategy is herein presented to overcome the problem of bulk carrier domination by using 3D TI nanoparticles, which are compacted by hot pressing to macroscopic nanograined bulk samples. Bi2Te3 nanoparticles well known for their excellent thermoelectric and 3D TI properties serve as the model system. As key enabler for this approach, a specific synthesis is applied that creates nanoparticles with a low level of impurities and surface contamination. The compacted nanograined bulk contains a high number of interfaces and grain boundaries. Here it is shown that these samples exhibit metallic-like electrical transport properties and a distinct weak antilocalization. A downward trend in the electrical resistivity at temperatures below 5 K is attributed to an increase in the coherence length by applying the Hikami–Larkin–Nagaoka model. THz time-domain spectroscopy reveals a dominance of the surface transport at low frequencies with a mobility of above 103 cm2 V−1 s−1 even at room temperature. These findings clearly demonstrate that nanograined bulk Bi2Te3 features surface carrier properties that are of importance for technical applications.
中文翻译：
纳米颗粒体 Bi2Te3 中的界面主导拓扑传输
具有极高迁移率的 3D 拓扑绝缘体 (TI) 宿主表面载流子。然而，它们的运输特性通常由散货船主导，散货船的数量超过水面运输船的数量级。本文提出了一种策略，通过使用 3D TI 纳米粒子来克服散装载流子支配的问题，该纳米粒子通过热压压缩成宏观纳米颗粒的散装样品。毕2特3以其优异的热电和 3D TI 特性而闻名的纳米粒子用作模型系统。作为这种方法的关键推动者，应用了一种特定的合成方法来制造具有低水平杂质和表面污染的纳米颗粒。压实的纳米晶粒块体包含大量界面和晶界。在这里表明，这些样品表现出类似金属的电传输特性和明显的弱反定位。温度低于 5 K 时电阻率的下降趋势归因于通过应用 Hikami-Larkin-Nagaoka 模型相干长度的增加。太赫兹时域光谱揭示了低频表面传输的主导地位，迁移率高于 10 3 cm 2 V -1s -1即使在室温下。这些发现清楚地表明，纳米颗粒体 Bi 2 Te 3具有对技术应用很重要的表面载体特性。
更新日期：2021-10-21
中文翻译：
纳米颗粒体 Bi2Te3 中的界面主导拓扑传输
具有极高迁移率的 3D 拓扑绝缘体 (TI) 宿主表面载流子。然而，它们的运输特性通常由散货船主导，散货船的数量超过水面运输船的数量级。本文提出了一种策略，通过使用 3D TI 纳米粒子来克服散装载流子支配的问题，该纳米粒子通过热压压缩成宏观纳米颗粒的散装样品。毕2特3以其优异的热电和 3D TI 特性而闻名的纳米粒子用作模型系统。作为这种方法的关键推动者，应用了一种特定的合成方法来制造具有低水平杂质和表面污染的纳米颗粒。压实的纳米晶粒块体包含大量界面和晶界。在这里表明，这些样品表现出类似金属的电传输特性和明显的弱反定位。温度低于 5 K 时电阻率的下降趋势归因于通过应用 Hikami-Larkin-Nagaoka 模型相干长度的增加。太赫兹时域光谱揭示了低频表面传输的主导地位，迁移率高于 10 3 cm 2 V -1s -1即使在室温下。这些发现清楚地表明，纳米颗粒体 Bi 2 Te 3具有对技术应用很重要的表面载体特性。
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