砷化鎘薄膜中之電傳輸現象

Electronic transport in Cd3As2 films

李潔瀅(Jie-Ying Lee)

指導教授 ： 梁啟德

國立臺灣大學/理學院/物理學研究所/碩士(2022年)

https://doi.org/10.6342/NTU202203347

摘要

砷化鎘(Cd3As2)材料早在1930年代就有許多凝態物理學領域的相關研究。砷化鎘在室溫下有著高電子遷移率(mobility)，且是一種狄拉克半金屬(Dirac semimetal)。在近幾年研究中，砷化鎘也能被應用於自旋閥元件，並有很好的量子傳輸特性。
本研究透過製程，把高品質的分子束磊晶成長砷化鎘薄膜做成霍爾元件，並展現其從低溫到室溫的磁傳輸特性。由霍爾電阻(Hall resistance)與縱向電阻率(longitudinal resistivity)的結果，可以得到載流子密度(carrier density)與載子遷移率。在垂直磁場下展現反弱局域(weak anti-localization)效應。在平行磁場下則同時展現反弱局域(weak anti-localization)效應與弱局域(weak localization)效應。並顯示這兩個效應的溫度相依性，並可以與相位相干長度(phase coherence length)的溫度相依性相互印證。

關鍵字

砷化鎘 ； 磁傳輸 ； 反弱局域效應 ； 弱局域效應

並列摘要

As early as in the 1930s, there has been a lot of related research in the fields of cadmium arsenide (Cd3As2) materials. Cadmium arsenide has a high electron mobility at room temperature and is a Dirac semimetal. In recent years, cadmium arsenide can also be used in spin valve devices, which have good quantum transport properties.
In this study, a high-quality molecular beam epitaxy grown cadmium arsenide film was fabricated into a Hall-bar device, and its magnetotransport properties from low temperatures to room temperature were studied. The carrier density and mobility can be obtained from the results of the Hall resistance and the longitudinal resistivity. It exhibits weak anti-localization effects in a perpendicular magnetic field. In a parallel magnetic field, both weak anti-localization effects and weak localization effects are exhibited. The temperature dependence of these two effects is shown and can be confirmed with the temperature dependence of the phase coherence length.

並列關鍵字

cadmium arsenide ； magnetotransport ； weak anti-localization effect ； weak localization effect

參考文獻

Chapter 1

[1] Conte, A. M., Pulci, O., Bechstedt, F. (2017). Electronic and optical properties of topological semimetal Cd3As2. Scientific Reports, 7, 45500

[2] Ali, M. N., Gibson, Q., Jeon, S., Zhou, B. B., Yazdani, A., Cava, R. J. (2014). The crystal and electronic structures of Cd3As2, the three-dimensional electronic analogue of graphene. Inorganic Chemistry, 53(8), 4062-4067.

[3] Li, H., He, H., Lu, H. Z., Zhang, H., Liu, H., Ma, R., Fan, Z., Shen, S.-Q., Wang, J. (2016). Negative magnetoresistance in Dirac semimetal Cd3As2. Nat. Commun. 7, 10301.

[4] Liu, Z. K., Jiang, J., Zhou, B., Wang, Z. J., Zhang, Y., Weng, H. M., Prabhakaran, D., Mo, S-K., Peng, H., Dudin, P., Kim, T., Hoesch, M., Fang, Z., Dai, X., Shen, Z. X., Feng, D. L., Hussain, Z., Chen, Y. L. (2014). A stable three-dimensional topological Dirac semimetal Cd3As2. Nature Materials 13(7), 677-681.