Weak Antilocalization in Bi 2 (Se x Te 1– x ) 3 Nanoribbons and Nanoplates
KAUST Grant NumberKUS-I1-001-12
Online Publication Date2012-01-25
Print Publication Date2012-02-08
Permanent link to this recordhttp://hdl.handle.net/10754/600187
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AbstractStudying the surface states of Bi 2Se 3 and Bi 2Te 3 topological insulators has proven challenging due to the high bulk carrier density that masks the surface states. Ternary compound Bi 2(Se xTe 1-x) 3 may present a solution to the current materials challenge by lowering the bulk carrier mobility significantly. Here, we synthesized Bi 2(Se xTe 1-x) 3 nanoribbons and nanoplates via vapor-liquid-solid and vapor-solid growth methods where the atomic ratio x was controlled by the molecular ratio of Bi 2Se 3 to Bi 2Te 3 in the source mixture and ranged between 0 and 1. For the whole range of x, the ternary nanostructures are single crystalline without phase segregation, and their carrier densities decrease with x. However, the lowest electron density is still high (∼10 19 cm -3) and the mobility low, suggesting that the majority of these carriers may come from impurity states. Despite the high carrier density, weak antilocalization (WAL) is clearly observed. Angle-dependent magnetoconductance study shows that an appropriate magnetic field range is critical to capture a true, two-dimensional (2D) WAL effect, and a fit to the 2D localization theory gives α of -0.97, suggesting its origin may be the topological surface states. The power law dependence of the dephasing length on temperature is ∼T -0.49 within the appropriate field range (∼0.3 T), again reflecting the 2D nature of the WAL. Careful analysis on WAL shows how the surface states and the bulk/impurity states may interact with each other. © 2012 American Chemical Society.
CitationCha JJ, Kong D, Hong S-S, Analytis JG, Lai K, et al. (2012) Weak Antilocalization in Bi 2 (Se x Te 1– x ) 3 Nanoribbons and Nanoplates . Nano Lett 12: 1107–1111. Available: http://dx.doi.org/10.1021/nl300018j.
SponsorsThe authors thank I. Fisher for the helpful discussions. Y.C. acknowledges support from the Keck Foundation, DARPA MESO Project (No. N66001-11-1-4105), and King Abdullah University of Science and Technology (KAUST) Investigator Award (No. KUS-I1-001-12).
PublisherAmerican Chemical Society (ACS)