Jin Hyunwoo, Kim Kwang-Chon, Seo Juhee, Kim Seong Keun, Cheong Byung-Ki, Kim Jin-Sang, Lee Suyoun
Center for Electronic Materials, Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea.
Nanoscale. 2015 Nov 7;7(41):17359-65. doi: 10.1039/c5nr05491e.
We investigated the magnetotransport properties of Bi2Te3 films grown on GaAs (001) substrate by a cost-effective metallo-organic chemical vapor deposition (MOCVD). We observed the remarkably high carrier mobility and the giant linear magnetoresistance (carrier mobility ∼ 22 000 cm(2) V(-1) s(-1), magnetoresistance ∼ 750% at 1.8 K and 9 T for a 100 nm thick film) that depends on the film thickness. In addition, the Shubnikov-de Haas oscillation was observed, from which the effective mass was calculated to be consistent with the known value. From the thickness dependence of the Shubnikov-de Haas oscillation, it was found that a two dimensional electron gas with the conventional electron nature coexists with the topological Dirac fermion states and dominates the carrier transport in the Bi2Te3 film with thickness higher than 300 nm. These results are attributed to the intrinsic nature of Bi2Te3 in the high-mobility transport regime obtained by a deliberate choice of the substrate and the growth conditions.
我们通过具有成本效益的金属有机化学气相沉积（MOCVD）研究了在GaAs（001）衬底上生长的Bi2Te3薄膜的磁输运特性。我们观察到了极高的载流子迁移率和巨大的线性磁阻（对于100nm厚的薄膜，在1.8K和9T时，载流子迁移率约为22000cm²V⁻¹s⁻¹，磁阻约为750%），且其依赖于薄膜厚度。此外，还观察到了舒布尼科夫-德哈斯振荡，据此计算出的有效质量与已知值相符。从舒布尼科夫-德哈斯振荡的厚度依赖性发现，具有传统电子性质的二维电子气与拓扑狄拉克费米子态共存，并在厚度大于300nm的Bi2Te3薄膜中主导载流子输运。这些结果归因于通过精心选择衬底和生长条件在高迁移率输运 regime中Bi2Te3的固有性质。
