| 报告题目 | Searching for unconventional quantum phases in conventional semiconductors |
| 报告人 | 常凯 教授 |
| 报告人单位 | State Key Laboratory for Superlattices and Microstructures Institute of Semiconductors Chinese Academy of Sciences |
| 报告时间 | 2014-12-11 |
| 报告地点 | 合肥微尺度物质科学国家实验室九楼会议室(9004室) |
| 主办单位 | 合肥微尺度物质科学国家实验室、国际功能材料量子设计中心 |
| 报告介绍 | 报告摘要：
Exploring novel quantum phases is always a central issue in condensed matter physics. In recent years, time-reversal symmetric topological phases (TI) have stimulated intensive interests due to its unique electronic structures and potential application ranging from spintronics to quantum computation. In this talk, I will present our recent works: 1)We analysis the relationship between Born-Oppenheimer approximation and quantum spin Hall effect (QSHE), and the origin of artificial gauge field. Based on this general designing principal, we propose that the TI can be realized in a conventional semiconductor InGaAs two-dimensional electron gas (2DEG), which possesses considerably large bandgap. 2)Utilizing interface polarization caused by strain and charge transfer, we find that several important semiconductors, such as InN, Ge, Si, can be driven into topological phases; 3)Mediated by helical surface states, the local spins on surface of 3D TIs can be correlated by the so called RKKY interaction. Using p-n junction, the remote local spins can also be correlated strongly. 4) We discussed the topological insulator nanostructures. We find the electron whispering gallery modes in TI quantum dots, which exhibit spin-angular momentum locking and harmonic oscillator-like energy spectra. We predict that the Aharonov-Bohm effect can be observed in semiconductor quantum dots. Finally we present our recent experimental study about practical application of topological insulators, e.g., photo-thermal effect.
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