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關于6月10日Ajit Srivastava學術報告的通知

編輯:phyjd 時間:2019年05月24日 訪問次數:186

題目:Single photons, phonons and spins in atomically thin WSe2

報告人:Prof. Ajit Srivastava, Emory College, America

地點: 教十二-201

時間: 610日,周一,14:00-15:00

摘要

Monolayer transition metal dichalcogenides (TMDs), such as WSe2, are atomically thin semiconductors with a valley degree of freedom, which can be optically addressed, thus opening up exciting possibilities for valleytronics". Recently, naturally occurring single quantum emitters, believed to be excitons trapped in shallow potentials, were reported in TMDs. They seem to inherit the valley degree of freedom from the host TMD and owing to their longer lifetimes, appear promising for quantum information processing applications.
In this talk, I will begin by highlighting some unique properties of TMDs excitons which result from the off-Gamma-point origin of the constituent single particle electronic states. After describing the basic properties of quantum dots in TMDs, I will present evidence for quantum entanglement between chiral phonons of the 2D host and single photons emitted from the quantum dots. I will also present evidence for optical initialization of single spin-valley in WSe2 FET devices. Finally, I will discuss our future plans for implementing a dynamically tunable array of qubits in pristine TMDs which can serve as an ideal platform for quantum information processing applications and also for understanding fundamental many-body physics.

個人簡介:

Dr. Srivastava is an Assistant Professor in the Department of Physics at Emory University since 2016. He earned his Bachelor’s degree from Indian Institute of Technology, Bombay and Masters and Doctorate degrees from Rice University. Prior to joining Emory, he was a postdoctoral researcher and later a senior scientist at ETH Zurich.

Research Area:

Condensed matter physics, quantum optics, strong light-matter interactions, physics of atomically thin 2D materials, role of geometry and topology in low-dimensions, Berry phase and artificial gauge fields, open systems.

Publications:

  1. "Materials in flatland twist and shine," Bernhard Urbaszek & Ajit Srivastava; Nature 567, 40 (2019).

  2. "Optical initialisation of a single spin-valley in charges WSe2 quantum dots," Xin Lu1, Xiaotong Chen1, Sudipta Dubey1, Qiang Yao, Weijie Li, Xingzhi Wang, Qihua Xiong, & Ajit Srivastava; Nature Nanotechnology (2019).

  3. "Entanglement of single-photons and chiral phonons in atomically thin WSe2,” Xiaotong Chen1, Xin Lu1, Sudipta Dubey1, Qiang Yao, Sheng Liu, Xingzhi Wang, Qihua Xiong, Lifa Zhang, & Ajit Srivastava, Nature Physics 15, 221-227 (2019).

  4. "At the flick of a switch," Ajit Srivastava, Nature Materials 17, 391–392 (2018). (News & Views)

  5. “Signatures of Bloch-band geometry on excitons: Nonhydrogenic spectra in transition-metal dichalcogenides,” A. Srivastava and A. Imamoglu, Phys. Rev. Lett. 115, 166802 (2015).

  6. “Optically active quantum dots in monolayer WSe2,” A. Srivastava, M. Sidler, A.V. Allain, D. S. Lembke, A. Kis, A. Imamoglu, Nature Nanotech. 10, 491-496 (2015).

  7. Valley Zeeman effect in elementary optical excitations of monolayer WSe2,” A. Srivastava, M. Sidler, A.V. Allain, D. S. Lembke, A. Kis, A. Imamoglu, Nature Phys. 11, 141-147 (2015).


歡迎老師和同學參加!