Lang, Murong and He, Liang and Kou, Xufeng and Upadhyaya, Pramey and Fan, Yabin and Chu, Hao and Jiang, Ying and Bardarson, Jens H. and Jiang, Wangjun and Choi, Eun Sang and Wang, Yong and Yeh, Nai-Chang and Moore, Joel and Wang, Kang L. (2013) Competing Weak Localization and Weak Antilocalization in Ultrathin Topological Insulators. Nano Letters, 13 (1). pp. 48-53. ISSN 1530-6984. https://resolver.caltech.edu/CaltechAUTHORS:20130212-114913918
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Abstract
We demonstrate evidence of a surface gap opening in topological insulator (TI) thin films of (Bi_(0.57)Sb_(0.43))_(2)Te_3 below six quintuple layers through transport and scanning tunneling spectroscopy measurements. By effective tuning the Fermi level via gate-voltage control, we unveil a striking competition between weak localization and weak antilocalization at low magnetic fields in nonmagnetic ultrathin films, possibly owing to the change of the net Berry phase. Furthermore, when the Fermi level is swept into the surface gap of ultrathin samples, the overall unitary behaviors are revealed at higher magnetic fields, which are in contrast to the pure WAL signals obtained in thicker films. Our findings show an exotic phenomenon characterizing the gapped TI surface states and point to the future realization of quantum spin Hall effect and dissipationless TI-based applications.
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| Additional Information: | © 2013 American Chemical Society. Published In Issue January 09, 2013; Article ASAP December 07, 2012; Just Accepted Manuscript November 30, 2012; Received: September 13, 2012; Revised: November 19, 2012. The authors acknowledge helpful discussions with R. Mong from UC Berkeley and technical support from X. Yu, M. Wang, J. Tang, and L. Chang from the Device Research Laboratory at UCLA. This work was in part supported by Defense Advanced Research Projects Agency (DARPA), Focus Center Research Program-Center on Functional Engineered Nano Architectonics (FENA). A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by NSF Cooperative Agreement No. DMR-0654118, by the State of Florida, and by the Department of Energy (DOE). Y.W. acknowledges the support from Natural Science Foundation of China (11174244) and Zhejiang Provincial Natural Science Foundation of China (LR12A04002) and National Young 1000 Talents Plan. | ||||||||||||||||||
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| Subject Keywords: | Topological insulator; ambipolar effect; surface states hybridization; ultrathin films; weak localization; weak antilocalization | ||||||||||||||||||
| Issue or Number: | 1 | ||||||||||||||||||
| Record Number: | CaltechAUTHORS:20130212-114913918 | ||||||||||||||||||
| Persistent URL: | https://resolver.caltech.edu/CaltechAUTHORS:20130212-114913918 | ||||||||||||||||||
| Official Citation: | Competing Weak Localization and Weak Antilocalization in Ultrathin Topological Insulators Murong Lang, Liang He, Xufeng Kou, Pramey Upadhyaya, Yabin Fan, Hao Chu, Ying Jiang, Jens H. Bardarson, Wanjun Jiang, Eun Sang Choi, Yong Wang, Nai-Chang Yeh, Joel Moore, and Kang L. Wang Nano Letters 2013 13 (1), 48-53 | ||||||||||||||||||
| Usage Policy: | No commercial reproduction, distribution, display or performance rights in this work are provided. | ||||||||||||||||||
| ID Code: | 36877 | ||||||||||||||||||
| Collection: | CaltechAUTHORS | ||||||||||||||||||
| Deposited By: | Jason Perez | ||||||||||||||||||
| Deposited On: | 13 Feb 2013 21:10 | ||||||||||||||||||
| Last Modified: | 09 Mar 2020 13:19 |
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