Ning Wei, Kong Fengyu, Han Yuyan, Du Haifeng, Yang Jiyong, Tian Mingliang, Zhang Yuheng
High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, Anhui, P. R. China.
1] High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, Anhui, P. R. China [2] Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China.
Sci Rep. 2014 Nov 18;4:7086. doi: 10.1038/srep07086.
While a two-dimensional (2D) metallic surface state in bismuth has been proposed, experimental 2D evidence of quantum transport, e.g., angular dependent Shubnikov-de Haas (SdH) oscillations is still lacking. Here, we report the angular-dependent magnetoresistance measurements in single-crystal Bi nanoribbons, and found that both the low-field weak antilocalization behavior and the high-field angle-dependent SdH oscillations follow exactly the 2D character, indicative of the 2D metallic surface states which dominate the transport properties of thin Bi nanoribbons. Moreover, by controllable exposing the ribbons to ambient environment (1 atm and room temperature), the metallic surface states were found to be robust to the oxidation although the carrier density in the surface states are modified after the exposures. These results suggest that the metallic surface states in Bi nanoribbons should be topologically protected which can provide key information in understanding the surface properties of Bi in nanometer scale.
虽然有人提出铋中存在二维（2D）金属表面态，但仍缺乏量子输运的实验二维证据，例如与角度相关的舒布尼科夫 - 德哈斯（SdH）振荡。在此，我们报告了在单晶铋纳米带中进行的与角度相关的磁电阻测量，并发现低场弱反局域化行为和高场角度相关的SdH振荡都完全符合二维特性，这表明二维金属表面态主导了薄铋纳米带的输运性质。此外，通过可控地将纳米带暴露于环境（1个大气压和室温）中，发现金属表面态对氧化具有鲁棒性，尽管暴露后表面态中的载流子密度发生了改变。这些结果表明，铋纳米带中的金属表面态应受到拓扑保护，这可为理解纳米尺度下铋的表面性质提供关键信息。
