| 1. |
- Jing, Yumei, et al.
(author)
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A Single-Electron Transistor Made of a 3D Topological Insulator Nanoplate
- 2019
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In: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 31:42
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Journal article (peer-reviewed)abstract
- Quantum confined devices of 3D topological insulators are proposed to be promising and of great importance for studies of confined topological states and for applications in low-energy-dissipative spintronics and quantum information processing. The absence of energy gap on the topological insulator surface limits the experimental realization of a quantum confined system in 3D topological insulators. Here, the successful realization of single-electron transistor devices in Bi2Te3 nanoplates using state-of-the-art nanofabrication techniques is reported. Each device consists of a confined central island, two narrow constrictions that connect the central island to the source and drain, and surrounding gates. Low-temperature transport measurements demonstrate that the two narrow constrictions function as tunneling junctions and the device shows well-defined Coulomb current oscillations and Coulomb-diamond-shaped charge-stability diagrams. This work provides a controllable and reproducible way to form quantum confined systems in 3D topological insulators, which should greatly stimulate research toward confined topological states, low-energy-dissipative devices, and quantum information processing.
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| 2. |
- Meng, Mengmeng, et al.
(author)
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Strong spin-orbit interaction and magnetotransport in semiconductor Bi2O2Se nanoplates
- 2018
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In: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 10:6, s. 2704-2710
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Journal article (peer-reviewed)abstract
- Semiconductor Bi2O2Se nanolayers of high crystal quality have been realized via epitaxial growth. These two-dimensional (2D) materials possess excellent electron transport properties with potential application in nanoelectronics. It is also strongly expected that the 2D Bi2O2Se nanolayers can be an excellent material platform for developing spintronic and topological quantum devices if the presence of strong spin-orbit interaction in the 2D materials can be experimentally demonstrated. Herein, we report the experimental determination of the strength of spin-orbit interactions in Bi2O2Se nanoplates through magnetotransport measurements. The nanoplates are epitaxially grown by chemical vapor deposition, and the magnetotransport measurements are performed at low temperatures. The measured magnetoconductance exhibits a crossover behavior from weak antilocalization to weak localization at low magnetic fields with increasing temperature or decreasing back gate voltage. We have analyzed this transition behavior of magnetoconductance based on an interference theory, which describes quantum correction to the magnetoconductance of a 2D system in the presence of spin-orbit interaction. Dephasing length and spin relaxation length are extracted from the magnetoconductance measurements. Compared to the case of other semiconductor nanostructures, the extracted relatively short spin relaxation length of ∼150 nm indicates the existence of a strong spin-orbit interaction in Bi2O2Se nanolayers.
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| 3. |
- Meng, Mengmeng, et al.
(author)
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Universal conductance fluctuations and phase-coherent transport in a semiconductor Bi2O2Se nanoplate with strong spin-orbit interaction
- 2019
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In: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 11:22, s. 10622-10628
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Journal article (peer-reviewed)abstract
- We report on phase-coherent transport studies of a Bi2O2Se nanoplate and on observation of universal conductance fluctuations and spin-orbit interaction induced reduction in fluctuation amplitude in the nanoplate. Thin-layered Bi2O2Se nanoplates are grown by chemical vapor deposition (CVD) and transport measurements are made on a Hall-bar device fabricated from a CVD-grown nanoplate. The measurements show weak antilocalization at low magnetic fields at low temperatures, as a result of spin-orbit interaction, and a crossover toward weak localization with increasing temperature. Temperature dependences of characteristic transport lengths, such as spin relaxation length, phase coherence length, and mean free path, are extracted from the low-field measurement data. Universal conductance fluctuations are visible in the low-temperature magnetoconductance over a large range of magnetic fields and the phase coherence length extracted from the autocorrelation function is consistent with the result obtained from the weak localization analysis. More importantly, we find a strong reduction in amplitude of the universal conductance fluctuations and show that the results agree with the analysis assuming strong spin-orbit interaction in the Bi2O2Se nanoplate.
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| 4. |
- Zhang, Mengmeng, et al.
(author)
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Aerodynamic Design Considerations and Shape Optimization of Flying Wings in Transonic Flight
- 2012
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In: 12th AIAA Aviation Technology, Integration, and Operations (ATIO) Conference and 14th AIAA/ISSM17 - 19 September 2012, Indianapolis, Indiana. - Reston, Virigina : American Institute of Aeronautics and Astronautics. - 9781600869303 ; , s. 1-17
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Conference paper (peer-reviewed)abstract
- This paper provides a technique that minimize the cruise drag (or maximize L/D) fora blended wing body transport with a number of constraints. The wing shape design isdone by splitting the problem into 2D airfoil design and 3D twist optimization with a frozenplanform. A 45% to 50% reduction of inviscid drag is nally obtained, with desired pitchingmoment. The results indicate that further improvement can be obtained by modifying theplanform and varying the camber more aggressively.
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